15 is 3/8 of what number?

If 15 is 3/8 of x (our number we are trying to find), the we can set up the equation:

15 = x * 3/8

15 * 8 = x * 3 (multiplied both sides by 8)

120 = 3x

120 / 3 = x (divided both sides by 3)

40 = x

Therefore, 15 is 3/8 of 40.

How i do it is 15/3=5 then 5 multiplied by 8 which gives you 40 (quicker answer)