Quantitative Aptitude
Time and Work
2,195 Questions
Time and Work Questions
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$10$ days
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$9$ days
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$8$ days
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$7$ days
A
Correct answer
Explanation
Let A take x days and B take x+5 days. Their combined rate is 1/x + 1/(x+5) = 1/6. Solving x^2 + 5x = 6(2x + 5) leads to x^2 - 7x - 30 = 0, which factors to (x-10)(x+3) = 0. Thus, A takes 10 days.
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$24hr,12hr,8hr$
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$20hr,8hr,12hr$
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$16hr,4hr,8hr$
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$12hr,8hr,20hr$
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$6$ days
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$8$ days
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$9$ days
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$5$ days
A
Correct answer
Explanation
B and C together complete 1/10 + 1/15 = 1/6 of the work per day. In 2 days, they complete 1/3 of the work, leaving 2/3 of the work remaining. A, who completes 1/9 of the work per day, will take (2/3) / (1/9) = 6 days to finish the remaining work.
A
Correct answer
Explanation
12 children * 16 days = 192 child-days. 8 adults * 12 days = 96 adult-days. So 1 adult = 2 children. Total work = 96 adult-days. 16 adults work for 3 days = 48 adult-days. Remaining work = 48 adult-days. New team: 6 adults (16-10) + 4 children (2 adults) = 8 adults. Days = 48 / 8 = 6 days.
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$10$ days
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$12$ days
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$8$ days
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$14$ days
B
Correct answer
Explanation
X does 1/8 per day, Y does 1/12, Z does 1/16. X works 2 days (2/8 = 1/4 work). Remaining is 3/4. Y works until 25% (1/4) is left for Z. So Y does 1/2 of the work. Y's time = (1/2) / (1/12) = 6 days. Z does 1/4 work in (1/4) / (1/16) = 4 days. Total time = 2 + 6 + 4 = 12 days.
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$6$ days
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$4$ days
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$12$ days
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$3$ days
D
Correct answer
Explanation
Work = Persons * Days. If P persons do W work in 12 days, 2P persons do W work in 6 days. Therefore, 2P persons do half the work (W/2) in 3 days.
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$dx - (100 - dy)$
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$dx - 100y$
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$dx - (100 - d)y$
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$dx+(100-d)y$
C
Correct answer
Explanation
The worker is employed for a total of 100 days. If he works for d days, he earns dx rupees. He is absent for the remaining (100 - d) days, which results in a deduction of (100 - d)y rupees. Therefore, his net earning E is given by dx - (100 - d)y.
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$\dfrac{30}{19} \ days$
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$\dfrac{30}{17} \ days$
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$\dfrac{40}{19} \ days$
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$\dfrac{40}{17} \ days$
A
Correct answer
Explanation
Work rates: A=1/3, B=1/5, C=1/10. Combined rate = 1/3 + 1/5 + 1/10 = (10+6+3)/30 = 19/30. Time = 1 / (19/30) = 30/19 days.
B
Correct answer
Explanation
B takes 60 days. A is 3 times as fast, so A takes 20 days. Together, they take (20 * 60) / (20 + 60) = 1200 / 80 = 15 days.
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$\displaystyle\frac{bc}{d+m}$
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$\displaystyle\frac{bc}{dm}$
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$\displaystyle\frac{b+c}{d+m}$
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$\displaystyle\frac{b+c}{dm}$
B
Correct answer
Explanation
Work = b * c. New work = (b * c) / m. Number of days = (Work / Men) = (bc / m) / d = bc / (dm).