2 men, 3 women and 5 boys together can complete a work in 10 days. A man does double the work a woman does and a woman does double the work a boy does. How many boys alone can complete 50% of the total work in 5 days?
2 men, 3 women and 5 boys together can complete a work in 10 days. A man does double the work a woman does and a woman does double the work a boy does. How many boys alone can complete 50% of the total work in 5 days? Correct Answer 19
2 men, 3 women and 5 boys together can complete a work in 10 days
According to the question
A man does double the work a woman does.
M = 2W
M : W = 2 : 1
Efficiency ratio of one man to one woman = 2 : 1 ----(1)
A woman does double the work a boy does.
W = 2B
W : B = 2 : 1
Efficiency ratio of one woman to one boy = 2 : 1 ----(2)
Multiply by 2 in equation (1)
Efficiency ratio of one man, one woman and one boy = 4 : 2 : 1
Total work = (2M + 3W + 5B) × 10 = (2 × 4 + 3 × 2 + 5 × 1) × 10 = (8 + 6 + 5) × 10 = 19 × 10 = 190
50% of the total work = 190 × = 190 × 1/2 = 95
Let x boys complete the 50% of the work in 5 days, then
x × B × 5 = 95
⇒ x × 1 × 5 = 95
⇒ x = 19 Boys