Question
The average mass of a group of girls was 35 kg. When a boy, Howard, joined the group, the average mass of the group became 30 kg. If Howard had a mass of 20 kg, how many girls were there in the group in the end?
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The average mass of a group of girls was 35 kg. When a boy, Howard, joined the group, the average mass of the group became 30 kg. If Howard had a mass of 20 kg, how many girls were there in the group in the end?