The ratio of house of babysitting and house is 3:2. If you change the 3 into a 15, you would have to change the 2 into a 10 because 3 x 5 = 15, so 2 x 5 = 10.
After you do those calculations you divide 15 by 5 and that is 3. You then multiply 60 by 3 = 180.
After that you have to divide 10 by 8 and you get 1.25. You then multiply 72 by 1.25 = 90.
