A can do 20% of a work in 4 days, B can do 33% of the same work in 10 days. They worked together for 9 days. C completed the remaining work in 6 days. B and C together will complete 75% of the same work in:
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 10 days
Concept
LCM approach to find total work.
Application
Time taken by A to complete 20% = 4 days
Time Taken by A to complete 100% work = 20 days
B can do 33% of the same work = 10 days
Time taken by B to do 100% work = 30 days
Therefore let total work = 60 units (LCM of 30 and 20)
A's efficiency = 3 units
B's efficieny = 2 units
Total work done by A and B in 9 days = 9 x ( 3+ 2)
= 45 units
Work Left = 60 - 45 = 15 days
It is completed by C in 6 days
C's efficient = 15 / 6 = 2.5 units
B & C will complete the 75 % of the work = (60 x 75 ) / 100 x 4.5 = 10 days