One worker finishes a job in 15 days and another worker finishes it in 12 days. How long will they take if they work together?
Answer and explanation
Correct answer: D. 20/3 days
- Step 1: Their daily rates are 1/15 and 1/12, which add up to 27/180, so the time is 180/27 = 20/3 days. Answer: 20/3 days. Why not the others: 13.5 days: averages the two times. 27 days: adds the two times. 3 days: subtracts the times.
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