Question

The mean (average) weight of three boys is 40 pounds. One of the boys weighs 50 pounds. The other two boys have the same weight. Find weight of each of the boys?

Answer 1

Answer: 35 lb, 35 lb, and 40 lb

Explanation:

(50+X+X)/3 = 40

50 + 2X = (40)(3)

2X = 120 - 50

X = 70/2

X = 35

Answer 2

The weights are 50 lb, 35 lb, and 35 lb.

Explanation:

The three boys weight x, y, and z pounds.

One boy weighs 50 lb, so x = 50. The other 2 boys have the same weight, so y = z.

The average weight is the sum of the three weights divided by 3.

(x + y + z)/3 = 40

(50 + y + y)/3 = 40

2y + 50 = 120

2y = 70

y = 35

z = y = 35

Answer: The weights are 50 lb, 35 lb, and 35 lb.