**Choose the most appropriate option.**

The average weight of three men ‘X’, ‘Y’ and ‘Z’ is 75 kgs. Another man ‘A’ joins the group and the average weight now becomes 80 kgs. If another person ‘B’ whose weight is 5 kgs more than ‘A’ replaces ‘X’, then the average weight of ‘Y’, ‘Z’, ‘A’ and ‘B’ will be 85 kgs. What is the weight of ‘X’s?

#### Options

78 kgs.

84 kgs.

82 kgs.

80 kgs.

#### Solution

**80 kgs.**

**Explanation:**

Here,

Average weight of three men X, Y and Z = 75 kgs.

∴ Total weight of three men X, Y and Z = 75 × 3 = 225 kgs.

A joins the group and average weight = 80 kgs

∴ Total weight of this group = 80 × 4 = 320 kgs.

∴ weight of A = 320 – 225 = 95 kgs.

∴ weight of B is 5 kg more than A.

∴ weight of B = 95 + 5 = 100 kgs.

Total weight of X, Y, A, and Z = 320 kgs.

Total weight of X, Y, AB and Z = 320 + 100 = 420 kgs.

Total weight of Y, Z, A and B = 85 × 4 = 340 kg.

∴ weight of X = (420 – 340) = 80 kgs.