A and B can complete a work in 10 days, B and C in 12 days, and C and A in 15 days. A alone can complete the work in
A30 days
B24 days ✓ Correct
C36 days
D32 days
Correct answer: (B) 24 days
Explanation
A alone takes 24 days.
Add the pairs: (A+B)+(B+C)+(C+A) = 1/10 + 1/12 + 1/15.
This equals 15/60 = 1/4, so 2(A+B+C) = 1/4.
Then A+B+C = 1/8; subtract (B+C) = 1/12.
A = 1/8 - 1/12 = 1/24, so A alone = 24 days.
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