Algebra
posted by Bobby .
Lisa had a box of apples. She gave 1/3 of them to henry and 1/4 of the remainder to ale. If there were still 30 apples left, how many did she have at the start?

This is really sort of a book keeping problem. Just keep track of the apples.
say x at start
(1/3) x to henry
leaves (2/3) x
(2/3) (1/4) = (1/6)x to ale
so
x  (1/3) x  (1/6) x = 30