42 raspberries, blackberries, and blueberries were picked in total. If half of all the berries had been raspberries, and a third of the berries were blackberries, how many of them were blueberries?
42/2 = <<42/2=21>>21 raspberries had been picked.
42/3 = <<42/3=14>>14 blackberries had been picked.
21+14 = <<21+14=35>>35 raspberries and blackberries had been picked.
42-35 = <<42-35=7>>7 blueberries had been picked.
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