Question

3 men and 4 boys can do a piece of work in 7 days. 2 men and 3 boys can do the same work in 10 days.How many days will aboy take to do it?​

Answer 1

here is the step by step explanation in my all in one reference book

• 2 men and 3 boys can do a piece of work in 10 days.

o Thus, 20 men and 30 boys can do a piece of work in 1 day......(i)

• 3 men and 2 boys can do the same work in 8 days.

o Thus, 24 men and 16 boys can do the same work in 1 day....(ii)

• Equating (i) and (ii) we get -

o 20 men + 30 boys = 24 men + 16 boys

o 4 men = 14 boys

o 2 men = 7 boys

• Substituting this in equation (i) we get

o 10 boys can do a piece of work in 10 days.

o But we need to find out in how many days 2 men and 1 boy can do the work, which is equivalent to 8 boys.

 8 boys can do the same work in (10*10/8) = 12.5 days.