Time and work Sheet Questions

A man ‘A’ can do a piece of work in 10 days, man ‘B’ can do the same piece of work in 12 days while man ‘C’ can do it in 15 days. They started work togetherbut after 2 days ‘A’ left the work and the remaining work was completed by ‘B’ and ‘C’ together. Find in how many days will the work be completed. 

A) 5 days

 B) 7 days 

C) 2 1/6 days 

D) 3 1/3 days

E) None of these 

Sol. (D) A…..10 =6unit 

B……12 Lcm=60 5unit

C…….15= 4unit 

Work of all 3 per day is 15 units (6+5+4) 

All 3 worked for 2 days. 

So 2 days work is 2*15=30units. Remaining (60-30)=30unit 

That work done by B and C their per day work unit (5+4)=9unit 

Remaining work done by B and C is 30/9=3 1/3 days