Correct Answer - Option 4 : 6 days
Given:
A, B, and C can do the work on their own in 5, 10, and 15 days respectively. We have to find the time required by B and C to complete the work together.
Concept Used:
Total work = LCM of their individual required time to complete the work
Calculation:
Total work = LCM of 5, 10, and 15 [We ignore time taken by A as only B and C work together and complete the work]
⇒ 30 units
B can do 30/10 = 3 unit work in 1 day
C can do 30/15 = 2 unit work in 1 day
B and C together can do (3 + 2) = 5 unit work in 1 day
Required time to complete the work = 30/5 = 6 days.
∴ Required time to complete the work by B and C is 6 days.
