Question 16

A man does double the work done by a boy in the same time. The number of days that 3 men and 4 boys will take to finish a work which can be done by 10 men in 8 days is

Solution

work done by man : work done by boy = 2: 1

let work done by a man in 1 day = 2 units

let work done by a boy in 1 day = 1 units

work done by 10 men in 8 days = 10 $$\times 2 \times 8$$ = 160 units

work done by 3 men and 4 boys in 1 day = $$3 \times 2 + 4 \times 1$$= 10 units

number of days = $$\frac{160}{10}$$ = 16 days