posted by Crystal .
you have 16 coins that are heads up and 18 coins that are tails up. After you add some coins that are tail up the ratio of heads up to tails up is 1:1.5. How many are tails up?
Heads up stay at 16
Ratio of 1:1.5 gives 16*1.5/1 = 24
Tails up original count = 18
Tails up added = 24-16 = 8