Aptitude - Average - Discussion

Discussion Forum : Average - General Questions (Q.No. 11)
11.
The average weight of A, B and C is 45 kg. If the average weight of A and B be 40 kg and that of B and C be 43 kg, then the weight of B is:
17 kg
20 kg
26 kg
31 kg
Answer: Option
Explanation:

Let A, B, C represent their respective weights. Then, we have:

A + B + C = (45 x 3) = 135 .... (i)

A + B = (40 x 2) = 80 .... (ii)

B + C = (43 x 2) = 86 ....(iii)

Adding (ii) and (iii), we get: A + 2B + C = 166 .... (iv)

Subtracting (i) from (iv), we get : B = 31.

B's weight = 31 kg.

Discussion:
41 comments Page 5 of 5.

Avneet said:   9 years ago
A + B + C = 45 * 3 = 135.
A + B = 40 * 2 = 80.
B + C = 43 * 2 = 86.

Now, (A + B + C ) - (A + B) = C i.e. 55,
Vice versa for the value of A i.e. 49.

Substitute the value of A in A + B = 80.
B will be 31.


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