Answer :

20 because 75% of 20 is 15

Answer: 20

Step-by-step explanation: In this problem, 15 is being represent as the part so we will have 15 over the part which we don't know which is going to be represented as 'x.' 75% is obviously the part which we will put over 100%.

Now, we can apply the cross products.

1500% = 75%x

X = 20