On a scale drawing of a swimming pool, 1 inch equals 4 feet. the actual dimensions of the swimming pool are 15 feet by 30 feet. what are the dimensions of the swimming pool in the scale drawing? explain your answer.

We are dealing with a scale drawing, so the measurements of the actual pool and that of the drawing are directly proportional.
If 1 inch on the drawing equals to 4 feet in real life, then the scale factor from sale drawing to the actual dimensions is ×4.
However we need the scale factor from the actual dimensions to those on the scale drawing. This value will be the reciprocal (1 over a given number) of the small to large scale factor, so is ×1/4, a.k.a a quarter.
Now we can find the scale drawing dimensions of the swimming pool by doing:

(and don't forget to use inches as the measurement for the scale drawing):

So 15 feet = 3.65 inches

And 30 feet = 7.5 inches.

The first option would be correct if it were one half and not one