The correct answer is 15 because if you make a graph you find 2.5 then go up to 15 because the graph would be linear
We need to solve the speed formula for d. To do so, let's start by moving the number of the left hand side:

Square both sides to get rid of the square root:

Now plug the known value of the speed to find the distance:

So the closest answer is the last one: d=0.155km
The confidence interval is

We first find p, our sample proportion. 118/200 = 0.59.
Next we find the z-score associated with this level of confidence:
Convert 98% to a decimal: 98% = 98/100 = 0.98
Subtract from 1: 1-0.98 = 0.02
Divide by 2: 0.02/2 = 0.01
Subtract from 1: 1-0.01 = 0.99
Using a z-table (http://www.z-table.com) we see that this value is associated with a z-score of 2.33.
The margin of error (ME) is given by

This gives us the confidence interval
Just divide 300 by 4 since 25% is 1/4
300/4 = 75
D. 75
Hope this helps!