Cody is a lifeguard and spots a drowning child 40 meters along the shore and 70 meters from the shore to the child. Cody runs along the shore for a while and then jumps into the water and swims from there directly to the child. Cody can run at a rate of 4 meters per second and swim at a rate of 1.1 meters per second. How far along the shore should Cody run before jumping into the water in order to save the child? Round your answer to three decimal places.
Answers
Answer:
Cody should run approximately 19.978 meters along the shore before jumping into the water in order to save the child.Thus,
Step-by-step explanation:
Consider the diagram below.
In this case we need to minimize the time it takes Cody to save the child.
Total time to save the child (T) = Time taken along the shore (A) + Time taken from the shore (B)
The formula to compute time is:
[tex]time=\frac{distance}{speed}[/tex]
Compute the time taken along the shore as follows:
[tex]A=\frac{x}{4}[/tex]
Compute the time taken from the shore as follows:
[tex]B=\frac{\sqrt{70^{2}+(40-x)^{2}}}{1.1}[/tex]
Then the total time taken to save the child is:
[tex]T=\frac{x}{4}+\frac{\sqrt{70^{2}+(40-x)^{2}}}{1.1}[/tex]
Differentiate T with respect to x as follows:
[tex]\frac{dT}{dx}=\frac{d}{dx}[\frac{x}{4}]+\frac{d}{dx}[\frac{\sqrt{70^{2}+(40-x)^{2}}}{1.1}][/tex]
[tex]=\frac{1}{4}-\frac{1}{1.1}\cdot \frac{(40-x)}{\sqrt{70^{2}+(40-x)^{2}}}[/tex]
Equate the derivative to 0 to compute the value of x as follows:
[tex]\frac{dT}{dx}=0[/tex]
[tex]\frac{1}{4}-\frac{1}{1.1}\cdot \frac{(40-x)}{\sqrt{70^{2}+(40-x)^{2}}}=0\\\\\frac{1}{1.1}\cdot \frac{(40-x)}{\sqrt{70^{2}+(40-x)^{2}}}=\frac{1}{4}\\\\4\cdot (40-x)=1.1\cdot [\sqrt{70^{2}+(40-x)^{2}}]\\\\\{4\cdot (40-x)\}^{2}=\{1.1\cdot [\sqrt{70^{2}+(40-x)^{2}}]\}^{2}\\\\16\cdot (40-x)^{2}=1.21\cdot [70^{2}+(40-x)^{2}}]\\\\16\cdot (40-x)^{2}-1.21\cdot (40-x)^{2}=5929\\\\14.79\cdot (40-x)^{2}=5929\\\\(40-x)^{2}=400.88\\\\40-x\approx 20.022\\\\x\approx 40-20.022\\\\x\approx 19.978[/tex]
Thus, Cody should run approximately 19.978 meters along the shore before jumping into the water in order to save the child.
Related Questions
anyone know the answer?
Answers
Answer:
B
Ive had this before
Help is needed please!!! Thanks Find the number of pairs of integers (x,y) with 0 1-(5/y)
Answers
Answer:
Técnicas orales y de cálculo mental de multiplicación y división entera . ... conjunto de múltiplos de 10 es un subconjunto de los números pares. Si ... La clase vacía ∅ se representa por la notación 0, la clase unitaria por 1, la clase binaria por 2, etc. En ... 5 x (5 x (5 x (5 + 4) + 3 ) + 2) + 1 ; x significa el signo de multiplicar. 8.
Step-by-step explanation:
Técnicas orales y de cálculo mental de multiplicación y división entera . ... conjunto de múltiplos de 10 es un subconjunto de los números pares. Si ... La clase vacía ∅ se representa por la notación 0, la clase unitaria por 1, la clase binaria por 2, etc. En ... 5 x (5 x (5 x (5 + 4) + 3 ) + 2) + 1 ; x significa el signo de multiplicar. 8.
Tyrone measured the floor of his rectangular storage unit. It is 3 feet wide and 8 feet from one corner to the opposite corner. How long is the storage unit? If necessary, round to the nearest tenth.
Answers
Answer:
Rounded to the nearest tenth, 7.4 feet long.
Step-by-step explanation:
Tyrone has a rectangular storage unit. We are given the width and the diagonal length.
So we can use Pythagorean Theorem.
3^2 + b^2 = 8^2
9 + b^2 = 64
subtract 9 from both sides
b^2 = 55
b = sqrt55
b is around 7.4161984871, so b rounded to the nearest tenth is 7.4 feet long.
what is the answer ，and how do you solve it .please help
Answers
Answer:
10
Step-by-step explanation:
2000/ 2x = 10
Multiply each side by 2x
2000/ 2x = 10 *2x
2000 = 20x
Divide by 20
2000/20 = 20x/20
100 = x
Take the square root of each side
sqrt(100) = sqrt(x)
10 = sqrt(x)
In a triangle ABC with |AB|=9m,|AC| =6m ,the sides AB and AC are produced to points X and Y respectively such that angleBXY=62°,and angle AYX=51°, calculate |BC| ..please help Mee♀️♀️
Answers
Answer:
|BC| = 9.4 m
Step-by-step explanation:
Angle bxy = angle abc (reason, corresponding angles)
Angle ayx = angle acb ( reason , corresponding angles)
So angle abc= 62°
Angle acb = 51°
Angle acb + and + bac = 180 (reason, sum of angles in a triangle)
Anlge bac = 180-62-51
Angle bac= 180-113
Angle back = 67°
Using sine formula
|BC| /sin 67 = 9/sin 62
|BC| = sin 67 *9/sin62
|BC| = 9.4 m
The figure below shows dimensions of a block of foam used to package a triangular shaped product. The foam is in the shape of a rectangular prism with a small triangular prism removed from the center. How many cubic centimeters of foam are used to package this product?
Answers
Answer:
5,580
Step-by-step explanation:
Rectangle: 36x30x60=6480
Triangle: 1/2x15x20x6=900
6480-900=5,580
The foam are used to package this product is cubic centimeters.
What is the volume of the rectangular prism?The Area of the rectangular prism is the product of the length, breadth, and height of the given prism.
Area of rectangular prism = 2(length x width + length x height + width x length)
Area of rectangular prism = 2( 36 x 30 + 30 x60 + 60 x 36)
= 10080 cubic centimeters
Let's find the base area:
The formula to find the base area is,
B = ½bh
Triangle area = 1/2 x 15 x 20 x 6
Triangle area = 900
10080 - 900 = 9180
Hence, the foam are used to package this product is cubic centimeters.
Learn more about rectangular prism;
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The shape on the left is translated to the shape on the right which statement about transformation is true?
Answers
heeelllpppppppppppppppp
Answers
Answer:
2/5m - 1/5
Step-by-step explanation:
2(1/5m - 2/5) + 3/5
= 2/5m - 4/5 + 3/5
= 2/5m - 1/5
Answer:
[tex]\frac{2m-1}{5}[/tex]
Step-by-step explanation:
[tex]2\left(\frac{1}{5}m-\frac{2}{5}\right)+\frac{3}{5}\\\\2\left(\frac{1}{5}m-\frac{2}{5}\right)=2\left(\frac{m}{5}-\frac{2}{5}\right)\\\\\frac{m}{5}-\frac{2}{5}=\frac{m-2}{5}\\\\=\frac{2\left(m-2\right)}{5}+\frac{3}{5}\\\\\mathrm{Apply\:rule}\:\frac{a}{c}\pm \frac{b}{c}=\frac{a\pm \:b}{c}\\\\=\frac{2\left(m-2\right)+3}{5}\\\\\mathrm{Expand}\:\left(m-2\right)\cdot \:2+3:\quad 2m-1\\\\=\frac{2m-1}{5}[/tex]
How do I solve 3(x+1)=5(x−2)+7?
Answers
Answer:
x = 3Step-by-step explanation:
[tex]3\left(x+1\right)=5\left(x-2\right)+7\\Expand\\3x+3 =5x -10+7\\Collect \:like\: terms\\3x-5x = -10+7-3\\-2x = -6\\Divide \:both\:sides\:of\:the\:equation\:by\:-2\\\frac{-2x}{-2} = \frac{-6}{-2}\\ \\x = 3[/tex]
Answer:
x = 3
Step-by-step explanation:
3(x+1)=5(x−2)+7
Use the distributive property to multiply 3 by x+1.
3x+3=5(x−2)+7
Use the distributive property to multiply 5 by x−2.
3x+3=5x−10+7
Add −10 and 7 to get −3.
3x+3=5x−3
Subtract 5x from both sides.
3x+3−5x=−3
Combine 3x and −5x to get −2x
−2x+3=−3
Subtract 3 from both sides.
−2x=−3−3
Subtract 3 from −3 to get −6.
−2x=−6
Divide both sides by −2.
x = -6/2
Divide −6 by −2
x = 3
Point R is on line segment QS. Given QR=3 and QS=17, determine the length RS.
Answers
Answer:
14
Step-by-step explanation:
RS = QS - QR
RS = 17 - 3
RS = 14
Answer:
[tex]\large \boxed{14}[/tex]
Step-by-step explanation:
Point R is on the line segment QS.
QS = QR + RS
Solve for RS.
RS = QS - QR
RS = 17 - 3
RS = 14
4. Given the following pattern of shapes, choose the mathematical expression showing th
changes for each iteration if b is the number of boxes in the previous iteration
a) b + 1
b) b + 2
c) 6-1
d) 6-2
Answers
Answer:
b)b+2
Step-by-step explanation:
3+2=5
5+2=7
so for the next iteration 2is added.
PLEASE HELPPP I'LL GIVE OUT BRAINLIEST !!!!!
Does (3, 3) make the equation y = 5x true?
Answers
Answer:
y = 5x
In the coordinate (3, 3), the first number is the x value and the second number is the y value.
So, does 3 = 5(3).
The answer is no, so this coordinate does not make the equation true.
Let me know if this helps!
Answer: No, the given point does not make the equation true.
===========================================================
Explanation:
There are three different ways to approach this.
One way is to plug x = 3 into the equation to find that
y = 5x
y = 5*3
y = 15
But that doesn't match up with y = 3 from the point (3,3). So we see that (3,3) is not a solution to y = 5x.
------
Or another method we could do is plug x = 3 and y = 3 to find a contradiction
y = 5x
3 = 5*3
3 = 15
The contradiction being that 3 on the left side doesn't match with 15 on the right side. The false equation at the end means y = 5x is false for (x,y) = (3,3), and therefore this point is not a solution to y = 5x.
------
The third method involves graphing the line y = 5x. You can see that (3,3) is not on the line, which visually confirms the results of the previous two sections. So for a point to be a solution, it must be on the line.
Find the slope of the line that passes through the points (-8,-3) and (2, 3)
0
1
3/5
5/3
Answers
Answer:
The answer is
[tex] \frac{3}{5} [/tex]Step-by-step explanation:
To find the slope passing through two points we use the formula
[tex]m = \frac{y2 - y1}{x2 - x1} [/tex]Where
m is the slope
( x1 , y1) and ( x2 , y2) are the points
From the question the points are
(-8,-3) and (2, 3)
So the slope is
[tex]m = \frac{3 + 3}{2 + 8} = \frac{6}{10} = \frac{3}{5} [/tex]Hope this helps you
A
A 30 m high pillar has been broken 10 m above from the ground. The tip of the broken part makes an angle of ...........with the ground
Answers
- 30m high pillar has been broken 10 m above ground = 20m
So,
sin0 = 10/20
sin0 = 1/2
= 30 degrees
H = 5 ft
Which is the formula
for the volume
of a cylinder?
A. V = a^2 + b^2 + c^2
B. V = (area of the base)(radius)
C. V = (area of the base)(height)
Answers
Answer: C. V = (area of the base)(height)
This applies to any prism. A cylinder is effectively a prism but the base is a circle rather than a polygon.
The cylindrical volume formula you may be more familiar with is
V = pi*r^2*h
note how the pi*r^2 portion is the area of the circular base. So we can replace the pi*r^2 with "area of the base" to end up with choice C.
what is 2x 3 -7x^{3}−7x 3
Answers
Answer:
It is given that
4x/3−7x/3=1
Step-by-step explanation:
By further calculation
−3x/3=1
So we get
−x=1
x=−1.
Pens cost 15 pence each.
Rulers cost 20 pence each.
A school buys 150 pens and 90 rulers.
The total cost is reduced by 1/5
How much does the school pay?
Answers
Answer:
The amount the school pays is £32.40
Step-by-step explanation:
The cost of each pen = 15 pence
The cost of each ruler = 20 pence
The number of pens bought by the school = 150
The number of rulers bought by the school = 90
The cost reduction (discount) on the items bought = 1/5
Therefore, we have;
The total cost of the pens bought by the school = 150 × 15 = 2250 = £22.50
The total cost of the rulers bought by the school = 90 × 20 = 1800 = £18.00
The total cost of the writing materials (rulers and pens) bought by the school = £22.50 + £18.00 = £40.50
The discount = 1/5 total cost reduction = 1/5×£40.50 = $8.10
The amount the school pays = The total cost of the writing materials - The discount
The amount the school pays = £40.50 - $8.10 = £32.40
The amount the school pays = £32.40.
A restaurant wanted to track how much of a quart of soda customers drank at a meal. The line plot displays the data collected by the restaurant. How much more soda did the customers who drank 3/4 of a quart drink than the customers who drank 1/4 of a quart?
Answers
Answer:
C
Step-by-step explanation:
13/4 simplified---->3and 1/4
A= 12b1+b2h ; solve for b1
Answers
Answer:
b1 = 2A/h – b2
Step-by-step explanation:
if you have a cylindrical tank that's 10 feet long and has a radius of 2 feet, what's the maximum possible capacity of the tank in gallons of water if 1 cubic foot of water = 7.48 gallons? Round your answer to two decimal places.
Answers
Answer:
Step-by-step explanation:
Volume = pi * r^2 * h
r = 2 feet
h = 10 feet
Volume = 3.14 * 2^2 * 10
Volume = 125.6 cubic feet
1 cubic foot contains 7.48 gallons
125.6 cubic feet contain 7.48 * 125.6 = 930.488
The tank contains 930.49 gallons.
If f(x)=-2x find x= -1
A.-3
B.-2
C.2
D.0
Answers
Roberto is x years older than his only sister but 10 years ago he was twice her age. What are the current ages of the siblings?
Answers
Answer:
S = x + 10
R = 2x + 10
Step-by-step explanation:
If R is Roberto's age, and S is his sister's age, then:
R = S + x
R − 10 = 2 (S − 10)
Solve with substitution.
S + x − 10 = 2 (S − 10)
S + x − 10 = 2S − 20
S = x + 10
R = 2x + 10
PLEASE HELP!! URGENT!! i will mark brainliest if its right!! In the figure below, ∠DEC ≅ ∠DCE, ∠B ≅ ∠F, and DF ≅ BD. Point C is the point of intersection between AG and BD while point E is the point of intersection between AG and DF. Prove ΔABC ≅ ΔGFE.
Answers
Answer:
See below.
Step-by-step explanation:
This is how you prove it.
<B and <F are given as congruent.
This is 1 pair of congruent angles for triangles ABC and GFE.
<DEC and <DCE are given as congruent.
Using vertical angles and substitution of transitivity of congruence of angles, show that angles ACB and GEF are congruent.
This is 1 pair of congruent angles for triangles ABC and GFE.
Now you need another side to do either AAS or ASA.
Look at triangle DCE. Using the fact that angles DEC and DCE are congruent, opposite sides are congruent, so segments DC and DE are congruent. You are told segments DF and BD are congruent. Using segment addition postulate and substitution, show that segments CB and EF are congruent.
Now you have 1 pair of included sides congruent ABC and GFE.
Now using ASA, you prove triangles ABC and GFE congruent.
which of the following is a quotient of the rational expressions shown here?
Answers
Answer:
x^2+x
--------
x-1
Step-by-step explanation:
x 1
------ ÷ --------
x-1 x+1
Copy dot flip
x x+ 1
------ * --------
x-1 1
x(x+1)
-------
x-1
x^2+x
--------
x-1
In the diagram, TC represents a vertical building. The points, A and B, are on the same level as the foot C of the building such that ATC = 40° and BTC = 56°. If BT is 29 m longer than AT, find
(a) the height of the building,
(b) the distance AB.
Answers
Answer:
(a) The height of the building is 60.06 m
(b) The distance AB is 139.43 m
Step-by-step explanation:
The given parameters are
Given that segment BT = segment AT + 29
By trigonometric ratios, we have;
cos∠ATC = CT/AT
cos∠BTC = CT/BT
Therefore, we have;
cos(40°) = CT/AT.................................(1)
cos(56°) = CT/BT = CT/(AT + 29).....(2)
cos(56°) = CT/(AT + 29)......................(3)
From equation (1)
CT = AT×cos(40°)
From equation (3)
AT×cos(56°) + 29 × cos(56°) = CT
Therefore;
AT×cos(40°) = AT×cos(56°) + 29 × cos(56°)
AT×cos(40°) - AT×cos(56°) = 29 × cos(56°)
AT×(cos(40°) - cos(56°)) = 29 × cos(56°)
AT = 29 × cos(56°)/(cos(40°) - cos(56°)) = 78.4 m
TC = CT = AT×cos(40°) = 78.4×cos(40°) = 60.06 m
The height of the building = 60.06 m
(b) BT = AT + 29 = 78.4 m + 29 m= 107.4 m
AB = AT×sin(∠ATC ) + BT×sin(∠BTC) = 78.4×sin(40°) + 107.4×sin(56°) = 139.43 m
The distance AB = 139.43 m.
Find the constant $p$ such that $x^2 - 5x + p$ is the square of a binomial.
Answers
Answer:
[tex]p = \frac{25}{4}[/tex]
Step-by-step explanation:
Given
[tex]x\² - 5x + p[/tex]
Required
Find p, such that the expression is a perfect square
Write out the coefficient of x
Coefficient = -5
Next step is to divide the coefficient of x by 2
[tex]Result = \½(-5)[/tex]
Take the square of the above expression to give p
[tex]p = (\½(-5))\²[/tex]
[tex]p = (\½(-5) * (\½(-5)[/tex]
[tex]p = \½ * \½ * (-5) * (-5)[/tex]
[tex]p = \¼(25)[/tex]
[tex]p = \frac{25}{4}[/tex]
Substitute 25/4 for p in the given expression
[tex]x\² - 5x + p[/tex] becomes
[tex]x\² -5x + \frac{25}{4}[/tex]
Expand the above expression
[tex]x\² - \frac{5x}{2} - \frac{5x}{2} + \frac{25}{4}[/tex]
Factorize
[tex]x(x - \frac{5}{2}) - \frac{5}{2}(x - \frac{5}{2})[/tex]
[tex](x - \frac{5}{2})(x - \frac{5}{2})[/tex]
[tex](x - \frac{5}{2})\²[/tex]
Hence, the value of p is [tex]p = \frac{25}{4}[/tex]
Which of the following is a point-slope equation of a line that passes through the points (-1,4) and (8,2)
Answers
Answer:
y - 2 = -2/9( x - 8)
Step-by-step explanation:
hope this helps
let me know if u need more help
Answer:
y - 2 = -2/9(x - 8) or y - 4 = -2/9(x + 1)
Step-by-step explanation:
find slope first
(2 - 4)/(8 - -1) = -2/9
y - 2 = -2/9(x - 8)
Find the area. Round to the nearest tenth.
6 in.
5 in.
9 in.
in.
Answers
Answer:
131 1/4 in.²
Step-by-step explanation:
To find the area of the figure, you would have to divide the figure into two parts. The figure can be divided into two rectangles.
Rectangle 1
The length is 11 3/4 in. The width is 6 in.
A = lw
A = (11 3/4 in.)(6 in.)
A = 70 1/2 in.²
Rectangle 2
The length is 9 in. The width is 6 3/4 in.
A = lw
A = (9 in.)(6 3/4 in.)
A = 60 3/4 in.²
Add the two areas together.
70 1/2 in.² + 60 3/4 in.² = 131 1/4 in.²
Alonso went to the market with \$55$55dollar sign, 55 to buy eggs and sugar. He knows he needs a package of 121212 eggs that costs \$2.75$2.75dollar sign, 2, point, 75. After getting the eggs, he wants to buy as much sugar as he can with his remaining money. The sugar he likes comes in boxes that each cost \$11.50$11.50dollar sign, 11, point, 50.
Answers
Answer:
2.75+11.50S[tex]\leq[/tex]55
4
Step-by-step explanation:
The Total amount of money Alonso went to the market with is: = $55
Items to be bought includes:
eggssugarAlonso knows that:
A pack of 12 eggs costs = $2.75 Now, he wants to use the remaining amount to purchase as much sugar as possibleRequirement for his taste for sugar:
a box of sugar he likes = $11.50From this information, the objective would be to determine the number of sugar he can purchase with the money left after he has already bought the eggs.
To start with, the amount of money left after buying the eggs is:
= $55 - $2.75
= $52.25
Now, if a box of sugar he likes cost = $11.50
Then he will be able to purchase (x( bost of sugar with = $52.50
Now, to determine the number of boxes of sugar he can purchase, we have:
1 box of sugar = $11.50
x(box) of sugar = $52.25
∴
[tex]\mathbf{x (box) of sugar = \dfrac{\$52.25 \times 1 box of sugar }{\$11.50}}[/tex]
x = 4.5 box of sugar
Therefore, after buying a pack of 12 eggs for = $2.75, Alonso will be able to buy [tex]\mathbf{ 4\dfrac{1}{2}}[/tex] or 4.5 boxes of sugar.
Learn more about word problems here:
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Is a 118 supplementary or complementary?pls ASAP!!
Answers
Answer:
[tex]\huge\boxed{Supplementary \ Angle}[/tex]
Step-by-step explanation:
118 is a supplementary angle. It is not a complementary angle because complementary angles add up to 90 and 118 is greater than 90 degrees. So, 118 is a supplementary angle and it is an angle adding up to 180 degrees with any other angle measuring 62 degrees.
Answer:Supplementary
Step-by-step explanation:You should remember that complementary refers to any number from 0-90 and supplementary refers to any number from 90 onwards..
Hereby giving the answer as ''Supplementary''