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The average weight of 15 steel balls is 70 kg. The average weight is increased by 2 kg when a steel ball weighing 12 kg is replaced by another, what is the weight of the new steel ball?

Answer 1:

Average weight of 15 balls = 70 kg

Therefore, total weight of 15 balls = 70*15 = 1050 kg

Now, weight of the new steel ball be x kg

New average = 1050-12+x/15 = 70+2

Therefore, x = 1080 - 1032 = 42 kg