Exam IIA-CIA-Part2 topic 2 question 7 discussion

Actual exam question from IIA's IIA-CIA-Part2

Question #: 7
Topic #: 2

A company owns a machine that will produce 100 light switches in four hours. Due to increased demand, a second machine capable of producing 100 light switches in three hours has been added.
Approximately how many hours will it take to produce 100 light switches using both machines working together?

A. 7.0
B. 3.5
C. 1.7
D. 0.58

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Suggested Answer: C 🗳️

by Emin at March 17, 2020, 2:34 p.m.

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CESSA

Highly Voted 3 months, 2 weeks ago

[Machine 1 = (100 swtches/4 hrs)] + [Machine 2(100 swtches/3hrs) ] = 59 swtches/ hr for both machines. = 100 (target production) /59 (switches for both machines) = 1.69 or 1.7 hrs

upvoted 10 times

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H_O

Most Recent 5 months, 3 weeks ago

In 3 hours total production is 100 + (100*3/4) = 175 3 hours : 175 units ? Hours : 100 units ? Hours = 3 x 100 / 175 = 1.7 hours Or In 4 hours total production is 100 + (100*4/3) = 233 4 hours : 233 units ? Hours : 100 units ? Hours = 4 x 100 / 233 = 1.7 hours

upvoted 3 times

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CABhawna

1 year ago

Second machine will produce 50 switches in 1.5 hours. At the same time, first machine can produce 37 switches (100/4*1.5). That is, in first 1.5 hours, total 87 switches can be produced by both the machines. Hence, for additional 13 switches a little more than 1.5 hours will be taken. Hence, 1.7 hours is the correct answer.

upvoted 2 times

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gml0603

1 year, 1 month ago

Not sure how to do calculation but seeing the answer 1.7 hours seems low. It would be helpful if all CIA answers are explained for why an answer is correct and why the other choices were incorrect

upvoted 2 times

Brad626

10 months, 1 week ago

I agree - other test question banks provide the explanations

upvoted 1 times

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Emin

1 year, 5 months ago

Which part of IIA-CIA does this question belong? It's just a GMAT question))