Question

you are a plumber installing a pipe the ratio of the outside diameter to the inside diameter is 1.5 to 1. you use a pipe with a 0.5 inch inside diameter what is the smallest diameter that you will need to drill to allow the pipes to pass through the wall

Answer 1

Since the outside is 1.5 to 1, we take half of the value of the inside diameter and add it to itself to get the smallest value needed. 0.5+0.25=0.75

So the smallest diameter possible would be 0.75 inches.