Question 31

The average weight of A, B and C is 49 kg. If the average weight of A and B is 35 kg and that of B and C is 62 kg, then the weight of B (in kgs) is?

Solution

$$\frac{A+B+C}{3}=49 \rightarrow A+B+C = 49\times 3 = 147$$ -------(1)

$$\frac{A+B}{2}=35 \rightarrow A+B = 35\times 2 = 70$$ -------(2)

$$\frac{B+C}{2}=62\rightarrow B+C = 62\times 2 = 124$$ -------(3)

(2)+(3)-(1)$$\Rightarrow A+B+B+C-A-B-C = 124+70-147$$

$$\Rightarrow B = 47$$

So the answer is option A.

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