The mistake he made is that he Yuri divided by n instead of n -1.
<h3>What mistake did he make?
</h3>
Standard deviation is used to determine how the values in a group differs from the mean of the values in the group.
In order to determine the standard deviation, take the following steps:
• Determine the mean of the observation: 14
Determine the difference between each value and the mean and then square the result: (12 - 14)² + (14 - 14)² + (9 - 14)² + (21 - 14)² = 78
Determine the mean of the sum of the squared differences and then find the square root of the mean: √78/(n - 1) = 5.1
To learn more about standard deviation, please check: brainly.com/question/26201837
#SPJ1
Let the number of weeks to have same amount = x Then:-
1200 + 40x = 700 + 50x
1200 - 700 = 50x - 40x
10x = 500
x = 50
answer is 50 weeks
Remember that you can do anything to an equation as long as you do it to both sides
so
I=PRT
divide both sides by RT
=P
P=?
I=40
R=10%=0.1
T=5
plug it in
=P
=P
80=P
answer is B, $80
Hi.
To find the unit rate we just need to divide the total cars washed in 5 hours (20) by the hours (5)
20 / 5 = 4
The unit rate is 4 cars/hour.
~