2 3
--- * ? = ---
9 15
We want to find the fraction represented by " ? " above.
We want to isolate the " ? " so mult both sides by the inverse of (2/9):
(9/2)(2/9) f = (3/15)(9/2) = 27/30 = 9/10
so the unknown fraction is 9/10.
Check your work: Is (2/9)(9/10) = 3/15? Is 1/5 = 1/5? YES.
