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?
Ivan spent a total of $10 - $3 = $<<10-3=7>>7 on cupcakes and a milkshake.
The cost of the cupcake is $10 x 1/5 = $<<10*1/5=2>>2.
So, $7 - $2 = $<<7-2=5>>5 was spent on the milkshake.
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