Question

A and B together can do a piece of work in 12 days which B and C together do in 16 days. If A works for 5 days, B works for 7 days than C complete the remaining work in 13 days. In how much time B alone do the whole work. 

(a) 48 days 

(b) 24 days 

(c) 16 days 

(d) 12 days

Answer 1

Correct option (a) 48 days

Explanation: 

According to questions

A worked for 5 days and B worked for 7 days

If A and B work together for 5 days they would complete 4×5 =20 units

remaining work =48-20=28 units Now B has to work for 2 more days and if he does it along with C for 2 days. 

Then, both would complete (3×2) = 6 units of 

work Work left = 28-6= 22 units 

Now C completes in 13-2 = 11 days

So, C works 22/1 = 2 unit/day

(efficiency) And B+C does 3 units/day (efficiency) So B does 1 unit/day

B will complete the whole work in 48/1= 48 days