Question

The average weight of 3 men A, B and C is 84 kg. Another man D joins the group and the average now becomes 80 kg. If another man E, whose weight is 3 kg more than that of D, replaces A, then the average weight of B, C, D and E becomes 79 kg. The weight of A is:

• A. 70
• B. 72
• C. 75
• D. 76
• E. 74

Answer 1

The correct option is C

75

Let A, B, C, D and E represent their respective weights. Then,

A + B + C = (84 x 3) = 252 kg

A + B + C + D = (80 x 4) = 320 kg

Therefore, D = (320 - 252) kg = 68 kg, E = (68 + 3) kg = 71 kg

B + C + D + E = (79 x 4) = 316 kg

Now,

(A + B + C + D) – (B + C + D + E) = (320 - 316) kg = 4 kg

Therefore, A – E = 4 $⟹$A = (4 + E) = 75 kg