Machine A can complete a task in 10 hours, and Machine B can complete the same task in 15 hours. If they work together, what fraction of the task will they complete in 3 hours?

A 1/5

B 1/4

C 1/2

D 3/5

✓ Correct Answer: Option C

Machine A's rate is 1/10 task/hour. Machine B's rate is 1/15 task/hour. Their combined rate is (1/10) + (1/15) = (3/30) + (2/30) = 5/30 = 1/6 task/hour. In 3 hours, they will complete 3 * (1/6) = 1/2 of the task.

💡 Why is C) the correct answer?

The correct answer to the question "Machine A can complete a task in 10 hours, and Machine B can complete the same task in 15 hours. If they work together, what fraction of the task will they complete in 3 hours?" is Option C: 1/2.

The other options — A) 1/5, B) 1/4, D) 3/5 — are incorrect for this GMAT Exam Prep question. As explained above: Machine A's rate is 1/10 task/hour. Machine B's rate is 1/15 task/hour. Their combined rate is (1/10) + (1/15) = (3/30) + (2/30) = 5/30 = 1/6 task/hour. In 3 hours, they will complete 3 * (1/6) = 1/2…

📚 About This GMAT Exam Prep Practice Question

This 2-level GMAT Exam Prep question from the Quantitative Reasoning topic is part of BrainForge Quiz's free exam preparation library. Each question includes the correct answer and a detailed explanation to help you understand the underlying concept, not just memorize the answer.

How to use this page: Read the question above, consider all four options (A through D), then check the highlighted correct answer and explanation. For active timed practice, start a free GMAT Exam Prep practice test or use flashcards for spaced repetition review.

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Machine A can complete a task in 10 hours, and Machine B can complete the same task in 15 hours. If they work together, what fraction of the task will they complete in 3 hours?

✓ Correct Answer: Option C

📚 About This GMAT Exam Prep Practice Question

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