Karan, Arjun and Krunal alone can complete a work in 20,

Solution

Let the total work = 120 units (LCM of 20, 30 and 24) Amount of work done by Karan alone in one day = 120/20 = 6 units Amount of work done by Arjun alone in one day = 120/30 = 4 units Amount of work done by Krunal alone in one day = 120/24 = 5 units Amount of work done by Karan, Arjun and Krunal together in 3 days = 3 × (6 + 4 + 5) = 45 units Amount of work done by Arjun and Krunal together in 5 days = 5 × (4 + 5) = 45 units Remaining work = 120 – 45 – 45 = 30 units So, the time taken by Krunal alone to complete 30 units work = 30/5 = 6 days So, Krunal worked for 6 + 5 + 3 = 14 days