Answer:
5.3 days
Step-by-step explanation:
Let us assume the loss of ability to recall a learned material = 100%
Formula to calculate number of days = time(t) =
t = t½ × Log½(Nt/No)
Nt = Ending Amount
No = Beginning Amount
t½ = Half life
t = Time elapsed
Therefore, we have the following values from the questions:
Half life (t½)= 35 days
Initial or beginning amount = 100%
Ending amount = 90%
t = t½ × Log½ (Nt/No)
t = 35 × Log ½(90/100)
t = 5.3201082705768 days
Approximately = 5.3 days
The blood platelet counts of a group of women have a bell-shaped distribution with a mean of 256.3 and a standard deviation of 66.8. (All units are 1000 cells/μL.) Using the empirical rule, find each approximate percentage below. a. What is the approximate percentage of women with platelet counts within 3 standard deviations of the mean, or between 55.9 and 456.7? b. What is the approximate percentage of women with platelet counts between 122.7 and 389.9?
Answer:
a) In the interval ( 55,9 ; 456,7 ) we will find 99,7 % of all values
b) In the interval ( 122,7 ; 389,9 ) we find 95,4 % of all values
Step-by-step explanation:
For a Normal distribution N (μ ; σ ) the Empirical rule establishes that the intervals:
( μ ± σ ) contains 68,3 % of all values
( μ ± 2σ ) contains 95,4 % of all values
( μ ± 3σ ) contains 99,7 % of all values
If N ( 256,3 ; 66,8 )
σ = 66,8 ⇒ 3*σ = 3 * 66,8 = 200,4
Then: 256,3 - 200,4 = 55,9
And 256,3 + 200,4 = 456,7
a) In the interval ( 55,9 ; 456,7 ) we will find 99,7 % of all values
b) 2*σ = 2 * 66,8 = 133,6
Then 256,3 - 133,6 = 122,7
And 256,3 + 133,6 = 389,90
Then in the interval ( 122,7 ; 389,9 ) we find 95,4 % of all values
8. If 30 cents out of every 1 dollar goes to taxes and the rest is net income, what's the
ratio of taxes to net income?
d
A. 30 : 7
B. 3:10
C. 30 : 1
D. 3:7
Answer:
D. 3:7Step-by-step explanation:
1 dollar = 30 cents tax + 70 cents net income
The ratio of taxes to net income:
30 : 70 = 3 : 7Correct choice is D
If 30cents are out then net income=100-30=70
ratio:-
[tex]\\ \rm\Rrightarrow \dfrac{30}{70}[/tex]
[tex]\\ \rm\Rrightarrow \dfrac{3}{7}[/tex]
[tex]\\ \rm\Rrightarrow 3:7[/tex]
A researcher is interested in finding a 90% confidence interval for the mean number of times per
day that college students text. The study included 147 students who averaged 44.7 texts per
day. The standard deviation was 17.9 texts. Round answers to 3 decimal places where possible.
a. To compute the confidence interval use a tv distribution.
b. With 90% confidence the population mean number of texts per day is between
and
texts.
Answer:
90% confidence the Population mean number of texts per day
(42.2561 ,47.1439)
Step-by-step explanation:
Step(i):-
Given sample size 'n' = 147
mean of the sample size x⁻ = 44.7
standard deviation of the sample 'S' = 17.9
90% confidence the Population mean number of texts per day
[tex](x^{-} - t_{\alpha } \frac{S}{\sqrt{n} } ,(x^{-} + t_{\alpha } \frac{S}{\sqrt{n} })[/tex]
Step(ii):-
Degrees of freedom
ν=n-1=147-1=146
t₀.₁₀ = 1.6554
[tex](x^{-} - t_{\alpha } \frac{S}{\sqrt{n} } ,(x^{-} + t_{\alpha } \frac{S}{\sqrt{n} })[/tex]
[tex](44.7 - 1.6554 \frac{17.9}{\sqrt{147} } ,(44.7 + 1.6554 \frac{17.9}{\sqrt{147} })[/tex]
(44.7 - 2.4439 ,44.7 + 2.4439 )
(42.2561 ,47.1439)
Conclusion:-
90% confidence the Population mean number of texts per day
(42.2561 ,47.1439)
The equation 8(y-3)= -40 is solved in several steps below. For each step, choose the reason that best justifies it.
Addition property of Equality
Subtraction Property of Equality
Multiplication property of equality
Division property of equality
simplifying
distributive property
Answer:
Step-by-step explanation:
The steps and their reasons for the equation 8(y - 3) = - 40 are given below.
What is the solution to the equation?The allocation of weights to the important variables that produce the calculation's optimum is referred to as a direct consequence.
The equation is given below.
8(y - 3) = - 40
Steps Reason
8(y - 3) = - 40 Given
8y - 24 = - 40 Distributive property
8y - 24 + 24 = - 24 + 24 Addition Property of Equality
8y = - 16 Simplifying
8y / 8 = - 16/8 Division property of equality
y = - 2 Simplifying
More about the solution of the equation link is given below.
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find out what's wrong with this graph
Answer:
The y-axis is upside down, meaning that instead of the values increasing as they go up, they decrease.
_____, as a defense mechanism, is the unconscious act of keeping threatening or disturbingthoughts, feelings, or impulses out of consciousness.
a. Sublimation
b. Projection
c. Reaction formation
d. Repression
Last month, a printing company printed $56,000.00 worth of books. This month, they printed $63,000.00 worth of books. What is the percent increase in their printing?
Solve this system of equations:
3x - 2y = -8
y=3/2x - 2
PLEASE WRITE THE STEPS
Hey there! I'm happy to help!
We see that y is equal to 3/2x-2. We can replace the y in the first equation with 3/2x-2 because they are equal and we can solve for x.
3x-2(3/2x-2)=-8
We use the distributive property to undo the parentheses.
3x-3x+4=-8
We combine like terms.
4=-8
We see that since there is no x anymore, there cannot be a solution. We have no x value to solve for the y value either, so there is no solution to this system of equations.
Have a wonderful day! :D
List the stem numbers below!!
Answer:
see below
Step-by-step explanation:
The stems are in the middle and the leaves are on the left and right
Stems are 0,1,2,3,4,5
Solve the inequality 7a + 13 < 48.
Hi there! :)
Answer:
[tex]\huge\boxed{a < 5}[/tex]
Given:
7a + 13 < 48
Isolate the variable "a" by subtracting 13 from both sides:
7a - 13 < 48 - 13
7a < 35
Divide both sides by 7:
7a/7 < 35/7
a < 5.
Answer:
a < 5
Step-by-step explanation:
7a + 13 < 48
Subtract 13 from each side
7a + 13-13 < 48-13
7a < 35
Divide each side by 7
7a/7 < 35/7
a < 5
The perimeter of the isoceles triangle is 54. The ratio of the leg to the base is 7:4. Find the length of the base
9514 1404 393
Answer:
12 units
Step-by-step explanation:
The ratio of the base to the other sides is ...
4 : 7 : 7
The perimeter is a total of 4 +7 +7 = 18 ratio units, so each ratio units stands for 54/18 = 3 length units.
The base length is then ...
(4 ratio units)(3 length units/ratio unit) = 12 length units
f(x) = 3x + 2
What is f(5)?
Answer:
17
Step-by-step explanation:
f(x) = 3x + 2
f(5) = 3(5) + 2
f(5) = 15 + 2
f(5) = 17
Answer:
17
Step-by-step explanation:
f(x) = 3x + 2
Plug in:
3(5) + 2
15 + 2 = 17
Hope this helped.
The cost in dollars y of producing x computer
desks is given by y = 40x + 4000
X
100
200
300
a. Complete the table
y
b. Find the number of computer desks that can be produced for $6200. (Hint: Find x when y = 6200.)
a. Complete the table.
х
100
200
300
y
b. For $6200,_ computer desks can be produced
Answer:
a.
y= 40x +4000
x= 100 --> y= 40(100)+4000= 4000+4000=8000
x=200 --> y= 40(200)+4000= 6000+4000= 10000
x=300 --> y= 40(300)+4000= 12000+4000= 16000
(in $)
b.
y= 40x+4000
6200= 40x+4000
6200-4000= 40x
2200= 40x
2200/40= x
55= x
(in unit)
Step-by-step explanation:
I hope this helps
if u have question let me know in comments ^_^
a can do a piece of work in 10 days and B can do in 15 days in how many days would they finish the work if they do it
A can do a piece of work in 10 days and B can do it 15 days. If both of them are working together, half of the work can be finished in?
Here we find,LCM of 10 and 15 is 30.
A can do ( 1 /10 th ) of the work in one day Or, ( 3/30th ).B can do ( 1/15th ) of the work in one day ( or 2/30th ).Working together, A and B can do
= (3/30) + (2/30) = 5/30= 1/6 th of the work in one day.So, they would require 30/5 or 6 days to complete the task.
Savannah used 2 quarts of paint on a summer project. She still had 5.
quarts of paint left when she was finished. How much paint did Savannah
have at first?
la cloud
Answer:
7 quarts
Step-by-step explanation:
total paint = paint used + paint left
total paint = 2 +5
total paint 7
Solve for x: −3|2x + 6| = −12.
Answer:
x = -1 or x = -5
Step-by-step explanation:
−3 * |2x + 6| = −12 / -3
|2x + 6| = 4
because this is an absolute value equation there are 2 solutions:
2x + 6 = 4 or 2x + 6 = -4
2x = -2 or 2x = -10
x = -1 or x = -5
Answer:
x = -1 or x = -5
Step-by-step explanation:
cuz it is
Determine which of the four levels of measurement (nominal, ordinal, interval, ratio) is most appropriate. Years in which U.S. presidents were inaugurated
Answer:
Interval Level of Measurement
Step-by-step explanation:
The Interval level of measurement highlights the distances between two measurements. These distances are meaningful and could be rated as low intervals or high intervals. Intervals also indicate class and order between measurements. The inauguration of the United States President is an event that occurs 72 to 78 days after the presidential election. It is usually done as a private and public oath-taking ceremony on January 20, four years after the last presidential election. So, even if the president is on a second term, this event must be held.
The last U.S presidential election occurred on January 20, 2017, and the next one will be held on January 21, 2021. So there is an interval of four years between the last and next U.S presidential inauguration ceremony.
What is the value of 1 in 1,255 is what times the value of the 1 in 82,175
Answer:
100,000
You take 1,000 because it's in the thousandths place of 1,255. The value of that one is 1,000 so you multiply that times 100, which is the value of 1 in 82,175.
Answer:
Step-by-step explanation:
What is the area of the regular polygon shown below?
Answer:
shown below..I can't see..
Answer:
93.5 for area
Step-by-step explanation:
there is no picture so that's a simple guess
which expression have a value of 2/3
A: 8+(24 divided by 12) X 4
B:8+24 divided by (12X4)
C: 8+24 divided 12X4
D: (8+24) divided (12X4)
The mathematics teacher proposes to his students that whoever determines their years of Experience as a teacher will have an extra point, for this they will have to solve the following expression
-5 + {4 * 6 + 3 + 1 + (3- (4-8) + (3-2)]}
How many years of experience does the teacher have?
Answer:
29 years of experience.
Step-by-step explanation:
So let's take the expression step by step. Remember that you need to follow the order of precedence here for the operations. Parentheses, exponentials, multiplication, and addition.
-5 + { 4 * 6 + 3 + 1 + [ 3 - ( 4 - 8 ) + ( 3 - 2 ) ] }
-5 + { 4 * 6 + 3 + 1 + [ 3 - ( -4 ) + ( 1 ) ] }
-5 + { 4 * 6 + 3 + 1 + [ 3 + 4 + 1 ] }
-5 + { 4 * 6 + 3 + 1 + [ 8 ] }
-5 + { 24 + 3 + 1 + 8 }
-5 + { 36 }
29
So the teacher has 29 years of experience.
Cheers.
A sample of bacteria is decaying according to a half-life model. If the sample begins with 700 bacteria, and after 10 minutes there are 140 bacteria, after how many minutes will there be 40 bacteria remaining? Round your answer to the nearest whole number.
Answer:
18 minutes
Step-by-step explanation:
A = A₀ (½)^(t / T)
where A is the final amount,
A₀ is the initial amount,
t is the time,
and T is the half life.
A = 140 when t = 10. Solve for the half life:
140 = 700 (½)^(10 / T)
0.2 = ½^(10 / T)
log 0.2 = (10 / T) log 0.5
10 / T = 2.32
T = 4.31
When A = 40, t is:
40 = 700 (½)^(t / 4.31)
0.057 = ½^(t / 4.31)
log 0.057 = (t / 4.31) log 0.5
t / 4.31 = 4.13
t = 17.8
Rounded to the nearest whole number, it takes 18 minutes.
The time taken for bacteria to reach 40 according to the exponential half-life decay formula is 18 minutes.
What is an exponential function?In mathematics, an exponential function is a relationship of the type y = ax, where x is an independent variable that spans the entire real number line and is expressed as the exponent of a positive number.
The half-life decay formula is given as,
N(t) = N₀ [tex](1/2)^{(t / T)}[/tex]
Where T is half-life while t is the time taken.
N₀ is the initial amount,
As per the given,
N(t) = 140 when t = 10.
140 = 700 [tex](1/2)^{(t / T)}[/tex]
Take log both sides,
log 0.2 = (10 / T) log 0.5
10 / T = 2.32
T = 4.31 minutes
Put N(t) = 40
40 = 700[tex](1/2)^{(t / 4.31)}[/tex]
Take log both sides,
log 0.057 = (t / 4.31) log 0.5
t / 4.31 = 4.13
t = 17.8 ≈ 18 minutes
Hence "The time taken for bacteria to reach 40 according to the exponential half-life decay formula is 18 minutes".
For more about exponential function,
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Please answer this correctly without making mistakes
Answer:
3 1/4
Step-by-step explanation:
Hey there!
Well if Cedarburg to Westford is 8 3/4 miles and Oxford to Westford is 5 1/2 miles, we can make the following,
CO = CW - OW
CO = 8 3/4 - 5 1/2
Make the denominators the same,
5 1/2
improper
11/2
*2
22/4
Proper
5 2/4
8 3/4 - 5 2/4
3 1/4 miles
Hope this helps :)
Labour costs, totalling $47.25, account for 63%
of a car repair bill. Calculate the total bill.
Answer:
75
Step-by-step explanation:
Let x = total bill
x*63% = 47.25
x *.63 = 47.25
Divide each side by .63
x*.63/.63 = 47.25/.63
x=75
Refer to △ABC. Find the length of side AB .
Step-by-step explanation:
Hello, there!!!!
It's simple lets get started with simple solution.....
Given,
AC= 7cm
BC= 25cm
let AB be x.
Now, As it is a Right angled triangle, taking angle B as a refrence angle. we get,
h= BC= 25cm
p= AC= 7cm
b= AB= x
now, by Pythagoras relation we get,
[tex]b = \sqrt{ {h}^{2} - {p}^{2} } [/tex]
[tex]or \: b = \sqrt{ {25}^{2} - {7}^{2} } [/tex]
By simplifying it we get,
b= 24cm
Therefore, the value of AB is 24 cm.
Hope it helps...
10/7p+13/8+15/2p=909/56 i NEED THiS solving multi step equations w fractions and #8 PLEASE
Answer:
P= 2
Step-by-step explanation:
10/7p+13/8+15/2p=-909/56
Combine like terms
10/7p+15/2p=-909/56-13/8
20p+105p/14=-909-13*7/56
125/14p=-909-91/56
125/14p= -1000/56
125/14p*14/125= -1000/56*14/125
simplify
P= 8/4=2
And for #8 n =1 I answered this question it
Search
Write an equation for a line perpendicular to y = − 5 x + 5 and passing through the point (5,5)
Answer:
The answer is
[tex]y = \frac{1}{5} x + 4[/tex]Step-by-step explanation:
Equation of a line is y = mx + c
where
m is the slope
c is the y intercept
To find the line perpendicular to
y = -5x + 5 we must first find the slope of
Comparing with the general equation above
Slope = - 5
The slope of the perpendicular line is the negative inverse of the slope of the original line
Slope of perpendicular line = 1/5
Equation of the line using point (5,5) and slope 1/5 is
[tex]y - 5 = \frac{1}{5} (x - 5)[/tex][tex]y - 5 = \frac{1}{5} x - 1[/tex][tex]y = \frac{1}{5} x - 1 + 5[/tex]We have the final answer as
[tex]y = \frac{1}{5} x + 4[/tex]Hope this helps you
Answer:
y=0.2x+4 or y=1/5 x+4.
Step-by-step explanation:
When one line is perpendicular to another, you have to find the opposite reciprocal for the slope of the given equation.
For instance, if you have the number 5, the reciprocal of 5 is 1/5 or 0.2. The opposite of positive is negative. Therefore, it is -0.2.
Therefore, if the slope of the first equation is -5, the slope for the next equation is 1/5. Reciprocal of -5 is -1/5. The opposite of -1/5 is positive 1/5. Or, the opposite of negative is positive. Therefore, it would be 1/5x.
However, we are not done.
Since we are given that the line passes through the point (5,5), we need to find the y-intercept of this equation.
The formula for slope-intercept is y=mx+b.
M is your slope
B is your y-intercept.
We can find the y-intercept by actually plugging in the point (5,5) into the new equation.
5=0.2(5)+b.
5 is x and 5 is also y.
(x,y).
Simplify the equation by multiplying 0.2 times 5. That is equal to 1.
We now have 5=1+b.
Isolate for the letter "b" by subtracting 1 from both sides.
1-1 is 0.
5-1 is 4.
Therefore, b=4.
Finally, we can plug in the y-intercept into the new equation.
y=0.2 or 1/5x+4.
I hope this helps! I also hope you have a great rest of your day!
Need Assistance
Please Show Work
Answer:
3 years
Step-by-step explanation:
Use the formula I = prt, where I is the interest money made, p is the starting amount of money, r is the interest rate as a decimal, and t is the time the money was borrowed.
Plug in the values and solve for t:
108 = (1200)(0.03)(t)
108 = 36t
3 = t
= 3 years
Which decimal is equivalent to
15/100?
A- O 0.015
B- 0.15
C-o 1.5
D- 0.0015
Answer:
D
Step-by-step explanation:
0.0015
hope this helps
What is the slope? Please Help
Answer:
-1
Step-by-step explanation:
Pick two points on the line
(0,2) and (2,0)
Using the slope formula
m = ( y2-y1)/(x2-x1)
= ( 0-2)/(2-0)
= -2/2
= -1
Answer:
-1
Step-by-step explanation:
Use two points on the line to find the slope, using rise over run.
We can use the points (0, 2) and (2, 0).
From the first point to the other, the y value decreases by 2 and the x value increases by 2.
Use rise (change in y value) over run (change in x value):
-2 / 2
= -1
So, the slope is -1.