Quantitative Aptitude • Time, Speed & WorkEasy
A can finish a piece of work in 10 days and B can finish it in 15 days. How many days will they take working together?
A. 5 days
B. 12.5 days
C. 6 days✓ Correct Answer
D. 25 days
💡 Solution & Explanation
In one day A does 1/10 of the work and B does 1/15. Together they do 1/10 + 1/15 = 1/6 of the work per day. So the whole work takes 6 days. Shortcut: ab ÷ (a + b) = 150 ÷ 25 = 6. Together they must be faster than either one alone.
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