All you have to do is divide 75 by .15. To start, you need to get rid of the decimal in .15, so move your decimal two spots to the right to turn .15 into 15. Then you have to move your decimal that is implied to be at the end of 75 over two spots because you moved the decimal in .15 which makes it 7,500. Now you have:
7,500 ÷ 15 = 500 500 is your answer.