A can do a certain work in 15 days. B is 25% more efficient than A. Both worked together for 4 days. C alone completed the remaining work in 8 days. A, B, and C together will complete the same work in?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 5 days.
Given :
A can do a certain work in 15 days
B is 25% more efficient than A
A and B do the work for 4 days remaining work is completed by C
Calculations :
B is 25% more efficient than A
⇒ (100/125) × 15
⇒ 12 days
Now, the LCM of 15 and 12 is 60
Efficiency of A = 60/15 = 4 units
Efficiency of B = 60/12 = 5 units
A and B work for 4 days = (4 + 5) × 4
⇒ 9 × 4 = 36 units
Remaining work = (60 - 36) = 24 units
The remaining work is completed by C in 8 days
⇒ 24/8 = 3 units per day
A, B, and C can complete the whole work
⇒ (60/(5 + 4 + 3))
⇒ 60/12 = 5 days