Question

A , B or C together can do piece of work in 15 day , B alone can do it in 30 day

Answer 1

Answer:

Step-by-step explanation:

A very easy and simple trick to do this is what I am going to share with you here.

A and B → 15 days

A → 20days

So, let's take LCM of 15 and 20. That's 60.

Remember: This 60 unit is the total work to be done.

So, A and B do (60/15) = 4 unit work/day …(1)

And, A does (60/20) = 3 unit work/day …(2)

(1)-(2) gives

B does (4–3)= 1 unit/day

So, Total days req. = (Total work)/unit per day

i.e, B can do it in (60/1)=60 days.