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 if A is-

A. 70 kg

B. 72 kg

C. 75 kg

D. 80 kg

Answer: Option C

Solution(By Examveda Team)

Let A, B, C, D and E represent their respective weights.
Then,
A + B + C = (84 × 3) = 252 kg
A + B + C + D = (80 × 4) = 320 kg
∴ D = (320 - 252) kg = 68 kg
E = (68 + 3) kg = 71 kg
B + C + D + E = (79 × 4) = 316 kg
Now,
= (A + B + C + D) - (B + C + D + E)
= (320 - 316) kg
= 4 kg
∴ A - E = 4
⇒ A = (4 + E)
⇒ A = 75 kg