math
posted by Anonymous .
A man decided to give 12 pieces of candy to each of the girls in his town and 8 pieces of candy to each of the boys. Of the 612 children in his town, only half the girls and three quarters of the boys were allowed to take the candy. How many pieces of candy did the gentleman have to buy?

Boys = b, Girls = 612  b
12 * (612b)/2 + 8 * 3/4b = ?
However, with the data given, I don't know how to find b.