GMAT Math Questions | GMAT Rates Q9

This GMAT quant question is a word problem in work and time. Concept: framing equations when two people with different efficiencies (rate at which they work) work together to complete a task. An easy, GMAT 600 level, quantitative reasoning question.

Question 9: Ram, who is half as efficient as Krish, will take 24 days to complete a task if he worked alone. If Ram and Krish worked together, how long will they take to complete the task?

1. 16 days
2. 12 days
3. 8 days
4. 6 days
5. 18 days

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Video Explanation

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Explanatory Answer | GMAT Time & Work Word Problem

Ram takes 24 days to complete the task, if he works alone.
Krish is twice as efficient as Ram is. So, working alone, Krish will take half the time to complete the task.i.e., 12 days.

Ram will complete \\frac{1}{24})^th of the task in a day.
Krish will complete \\frac{1}{12})^th of the task in a day.
When they work together, they will complete \\frac{1}{24} + \frac{1}{12} = \frac{1}{8})^th of the task in a day.

Therefore, when they work together they will complete the task in 8 days.

Choice C is the correct answer.