A and B can do a work in 12 days and 18 days, respectively. They worked together for 4 days after which B was replaced by C and the remaining work was completed by A and C in the next 4 days. In how many days will C alone complete 50% of the same work?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 18
Let the total work = 36 units
A does 3 units a day and B does 2 units a day.
Thus, A and B do 5 units a day together.
They do 20 units in 4 days. After that 16 units are left which are done by A and C in 4 days.
A and C do 4 units a day.
If A does 3 units a day, C does 1 unit a day.
C does 18 units in 18 days.