Ivan had $10 and spent 1/5 of it on cupcakes. He then spent some money on a milkshake and had only $3 left. How much is the milkshake?
Thoughts? Step-by-step reasoning:
Ivan spent a total of $10 - $3 = $7 on cupcakes and a milkshake. The cost of the cupcake is $10 x 1 / 5 = $2. So, $7 - $2 = $5 was spent on the milkshake.
Thus, the answer is 5.