Question

2 men or 3 boys take 40 hours to do a certain piece of work. How long will 4 men and 9 boys take to
complete the work?​

Answer 1

Answer: hours

Step-by-step explanation:

Let's rephrase the question 3 boys take 40 hours to do a certain piece of work. How long will 9 boys take to

complete the work?

Using inverse proportion, we have

3 boys do a work in 40 hours that is

3 × 40 = 120 boy hours

That is 1 boy can do the work in 120 hours.

Therefore 9 boys can do this work in 120 ÷ 9 = 13 hours 18 minutes