The average weight of a group of 10 girls is 48 kg. If 2 girls R and S replace P and Q, then the new average weight is 46 kg. The weight of P is equal to the weight of Q and the weight of R is equal to the weight of S, another girl T joins the group, and the new average weight of the group becomes 46 kg. The weight of T is equal to the weight of R. What is the weight of Q (in kg)?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 56.
Total weight of 10 girls = 480
According to the given question,
480 - P - Q + R + S = 460
⇒ 480 - 2Q + 2R = 460
Also, 460 + T = 46 × 11
⇒ T = 506 - 460
⇒ T = R = 46
Now, 2Q - 2(46) = 20
⇒ 2Q = 20 + 92
⇒ 2Q = 112
⇒ Q = 56