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Question : The average weight of 10 boys is increased by 3kg if one of them weighing 40 kg is replaced by a new boy. The weight of the new boy is:

Option 1: 45 kg

Option 2: 70 kg

Option 3: 80 kg

Option 4: 40 kg


Team Careers360 23rd Jan, 2024
Answer (1)
Team Careers360 25th Jan, 2024

Correct Answer: 70 kg


Solution : Let the average weight of 10 boys be $x$.
The sum of weights of 10 boys = $10x$
New average weight = $x+3$
New sum of weights = $10(x+3) = 10x+30$
Let the weight of the new boy be $y$.
So, $10x-40+y=10x+30$
⇒ $y=30+40=70$
Hence, the correct answer is 70 kg.

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