Use the depreciation formula.

Where 'p' is the principal value, 'r' is the rate it depreciates, and 'n' is the time. Just plug in what we know:

Simplify by subtracting:

Simplify the exponent:

Multiply:
Distance between Brad and bombs falling location we need
- Hypotenuse=H=41m
- Perpendicular=P=40m
Base be B
Apply Pythagorean theorem
- B²=H²-P²
- B²=41²-40²
- B²=9²
- B=9m
Answer:
A sample size of 35 is needed.
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 width W as such

In which
is the standard deviation of the population and n is the size of the sample.
How large must the sample size be if the width of the 95% interval for mu is to be 1.0:
We need to find n for which W = 1.
We have that
, then
. So





Rounding up
A sample size of 35 is needed.