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Machine A can produce a case of nails in 15 hours. Machine B can produ
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09 Jun 2021, 00:25
09 Jun 2021, 00:25
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Machine A can produce a case of nails in 15 hours. Machine B can produce a case of nails in 12 hours. When both machines are running at the same time, how many hours will it take to produce nine cases?
20
40
54
60
75
Kudos for the right answer and explanation
Question part of the project GRE Quantitative Reasoning Daily Challenge - (2021) EDITION
GRE - Math Book
20
40
54
60
75
Kudos for the right answer and explanation
Question part of the project GRE Quantitative Reasoning Daily Challenge - (2021) EDITION
GRE - Math Book
Re: Machine A can produce a case of nails in 15 hours. Machine B can produ
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09 Jun 2021, 07:52
09 Jun 2021, 07:52
2
Machine A = 15 hours
Machine B = 12 hours
When working together to produce one case = \(\frac{15 * 12}{15 + 12}\) = \(\frac{180}{27}\) = \(\frac{20}{3}\) hours
To produce 9 cases = \(\frac{20}{3}\)*9 = 60 hours
Answer D
Machine B = 12 hours
When working together to produce one case = \(\frac{15 * 12}{15 + 12}\) = \(\frac{180}{27}\) = \(\frac{20}{3}\) hours
To produce 9 cases = \(\frac{20}{3}\)*9 = 60 hours
Answer D
Re: Machine A can produce a case of nails in 15 hours. Machine B can produ
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17 Jun 2021, 20:51
17 Jun 2021, 20:51
Since the two machine are working together, we can add their rates
1/15+1/12= 9/60 ==> the 2 machine can produce 9 cases in 60 minutes.
Answer is D
1/15+1/12= 9/60 ==> the 2 machine can produce 9 cases in 60 minutes.
Answer is D
