<human>:  Melissa bought 4 packs of tennis balls for $24 in total. Each pack contains 3 balls per pack. How much did it cost Melissa for each tennis ball?
<bot>: How many balls are in each pack? ** There are 4 packs of tennis balls while each pack has 3 balls. 4 * 3 = <<4*3=12>>12 balls
How much did it cost Melissa for each tennis ball? ** Melissa spent a total of $24 for a total of 12 balls. $24 / 12 = $<<24/12=2>>2 per ball
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