Answer:
Time required by Ben was 12 minutes.
Step-by-step explanation:
Given:
Time Required for Fred = 16 mins
Ben completed his run in 3/4 of the amount of time of Freds run.
We need to find the time required by Ben.
Now Given that;
Ben completed his run in 3/4 of the amount of time of Freds run.
It means that time required by Ben is equal to 3/4 times time required by Fred.
Time required by Ben = 
Time required by Ben = 
Hence Time required by Ben was 12 minutes.
Answer:
Step-by-step explanation:
L = 3*w + 1 Given
P = 2*(L + w) Formula for Perimeter. Substitute for L
P = 2*(3w + 1 + w) Combine
P = 2*(4w + 1)
P = 58 Given
58 = 8w + 2 Remove the brackets
58 - 2 = 8w Subtract 2
56 = 8*w Divide by 8
56/8 = w
7 = w
================
Find L
L = 3*w + 1
L = 3*7 + 1
L = 22
================
Check
2L + 2W = 58
2*22 + 2*7 =? 58
44 + 14 = ? 58
58 = 58
The answer checks.
I think it would have crystal formations if I remember correctly.
Answer:
We need to sample at least 1069 parents.
Step-by-step explanation:
We have that to find our
level, that is the subtraction of 1 by the confidence interval divided by 2. So:

Now, we have to find z in the Ztable as such z has a pvalue of
.
So it is z with a pvalue of
, so 
Now, find the margin of error M as such

In which
is the standard deviation of the population and n is the size of the sample.
How many parents do you have to sample?
We need to sample at least n parents.
n is found when
. So






Rounding up
We need to sample at least 1069 parents.