Question

K alone can complete a work in 20 days and M alone can complete the same work in 30 days. K and M start the work together but K leaves the work after 5 days of the starting of work. In how many days M will complete the remaining work?

• A. 35/2
• B. 25/2
• C. 55/2
• D. 45/2

Answer 1

Answer:

A. 35/2

Solution: Given: K alone can complete a work in 20 days M alone can complete the same work in 30 days K and M start the work together but K leaves the work after 5 days Formula Used: Total Work = One day Work × Number of Days Calculation: Total work = LCM (20, 30) = 60 ⇒ One day work of K = 60/20 = 3 ⇒ One day work of M = 60/30 = 2 For the first 5 days (K + M ) together done the work ⇒ One day work of (K + M) = 3 + 2 = 5 ∴ The work completed in 5 days = 5 × 5 = 25 And the Remaining work = 60 – 25 = 35 The remaining work to be done by M alone ∴ Number of days M takes to complete the remaining work = 35/2 days