One worker finishes a job in 12 days and another worker finishes it in 30 days. How long will they take if they work together?
Answer and explanation
Correct answer: C. 60/7 days
- Step 1: Their daily rates are 1/12 and 1/30, which add up to 42/360, so the time is 360/42 = 60/7 days. Answer: 60/7 days. Why not the others: 21 days: averages the two times. 42 days: adds the two times. 18 days: subtracts the times.
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