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If Sabrina can assemble a tank in 8 hours, and Janis can assemble a
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25 Jul 2025, 23:09
25 Jul 2025, 23:09
Expert Reply
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Question Stats:
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If Sabrina can assemble a tank in 8 hours, and Janis can assemble a tank in 13 hours, then Sabrina and Janis working together at their constant respective rates can assemble a tank in approximately how many hours?
(A) 21
(B) 18
(C) 7
(D) 5
(E) 2
(A) 21
(B) 18
(C) 7
(D) 5
(E) 2
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Re: If Sabrina can assemble a tank in 8 hours, and Janis can assemble a
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03 Aug 2025, 22:28
03 Aug 2025, 22:28
Expert Reply
Sabrina can assemble a tank in 8 hours, so her rate is
$$
\(\frac{1 \text { tank }}{8 \text { hours }}=\frac{1}{8} \text { tank per hour. }\)
$$
Janis can assemble a tank in 13 hours, so her rate is
$$
\(\frac{1 \text { tank }}{13 \text { hours }}=\frac{1}{13} \text { tank per hour. }\)
$$
Working together, their combined rate is:
$$
\(\frac{1}{8}+\frac{1}{13}=\frac{13}{104}+\frac{8}{104}=\frac{21}{104} \text { tanks per hour. }\)
$$
Time taken together to assemble one tank is the reciprocal of their combined rate:
$$
\(t=\frac{1}{\frac{21}{104}}=\frac{104}{21} \approx 4.95 \text { hours. }\)
$$
Final answer:
Approximately 5 hours.
Answer: (D) 5
$$
\(\frac{1 \text { tank }}{8 \text { hours }}=\frac{1}{8} \text { tank per hour. }\)
$$
Janis can assemble a tank in 13 hours, so her rate is
$$
\(\frac{1 \text { tank }}{13 \text { hours }}=\frac{1}{13} \text { tank per hour. }\)
$$
Working together, their combined rate is:
$$
\(\frac{1}{8}+\frac{1}{13}=\frac{13}{104}+\frac{8}{104}=\frac{21}{104} \text { tanks per hour. }\)
$$
Time taken together to assemble one tank is the reciprocal of their combined rate:
$$
\(t=\frac{1}{\frac{21}{104}}=\frac{104}{21} \approx 4.95 \text { hours. }\)
$$
Final answer:
Approximately 5 hours.
Answer: (D) 5
gmatclubot
Re: If Sabrina can assemble a tank in 8 hours, and Janis can assemble a [#permalink]
03 Aug 2025, 22:28
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