A can finish a piece of work in 48 days and B can finish it in 60 days . They work together for 12 days and then A goes away. In how much time ( in days and hours) will B finshed 25% of the remaining work ?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 8 days 6 hours
Solution :
Let the total work (LCM of 48 and 60) be 240 units.
Efficiency of A = 240/48 = 5 units/day
Efficiency of B = 240/60 = 4 units/day
They worked together for 12 days, so the work done by (A + B) in 12 days = (5 + 4) × 12 = 108 units.
The remaining work = (240 - 108) = 132 units
The time taken by B alone to complete 25 % of the remaining work
⇒ [132 × (25/100)]/4 = 33/4 = days
Hence the required time = 8 days 6 hours