Question
MCQ} A and B together can finish a project in days. B alone takes days to finish the project. They start the project together, but A leaves after some days; B alone then takes a further days to complete the remaining work. The number of days A alone would take to complete the project is:
Options
Answer
(B) .
Detailed solution
Combined rate of A and B . B's rate .
So A's rate
Therefore A alone takes days.
Consistency check with the third datum: Let A and B work together for days, then B alone for days. Total work: days. Consistent.
Why this is CAT-level: The redundant `` days'' datum tempts students into setting up a two-variable equation system. The elegant route uses only the first two facts, with the third merely confirming consistency. Method selection -- not method execution -- is what saves time.
Answer: (B) .