Quantitative Aptitude
Time and Work
2,195 Questions
Time and Work Questions
A
Correct answer
Explanation
Using inverse variation: More days means fewer women. Total work = 42 × 18 = 756 woman-days. For 21 days: 756 ÷ 21 = 36 women. Option A is correct. Option 24 would be correct if days increased more than proportionally. Option 30 and 44 don't satisfy the inverse relationship.
B
Correct answer
Explanation
Work and laborers are inversely proportional to time (more laborers = less time). 120 laborers × 15 days = 1800 laborer-days. For 10 days: 1800 ÷ 10 = 180 laborers needed.
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10 days
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15 days
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20 days
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25 days
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22 days
B
Correct answer
Explanation
Let 1 man's 1 day work = m, 1 woman's 1 day work = w. 5m × 15 = 1 (total work). Work done in first 5 days = 5m × 5 = 1/3. Remaining work = 2/3. In next 5 days: (5m + 10w) × 5 = 2/3, so 5m + 10w = 2/15. Since 5m = 1/15, we get 1/15 + 10w = 2/15, so 10w = 1/15. If 10 women do the work alone: Time = 1/(10w) = 1/(1/15) = 15 days. Option B is correct.
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38 days
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30 days
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23 days
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26 days
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19 days
E
Correct answer
Explanation
Let B's efficiency = 1 unit/day. Then A's efficiency = 1.3 units/day (30% more). Let total work = W. B works for 12 days: work done = 12 units. Remaining work = W - 12. A completes this in 20 days: 1.3 × 20 = 26 units = W - 12. Therefore W = 38 units. B's rate = 1 unit/day, so B alone takes 38 days for full work. For half the work: 38/2 = 19 days.
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8 days
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24 days
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36 days
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48 days
D
Correct answer
Explanation
Work rate of Ram + Shyam = 1/16 per day. Ram's rate = 1/24 per day. Shyam's rate = (1/16) - (1/24) = (3-2)/48 = 1/48 per day. Therefore, Shyam alone completes the work in 48 days.
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8
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7
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12
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14
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can't be determined
B
Correct answer
Explanation
Let 1 man's work = 1 unit/day. Then 1 woman = 2 units, 1 boy = 0.5 units. Combined work per day = 3(1) + 4(2) + 6(0.5) = 3 + 8 + 3 = 14 units. Total work = 14 × 7 = 98 units. For 7 women: work per day = 7 × 2 = 14 units. So 7 women complete 98 units in 98/7 = 7 days.
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6 days
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8 days
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5 days
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4 days
A
Correct answer
Explanation
Let Ram take 2x days, Shyam take x days, and Mohan take 2x/3 days. Their combined rate: 1/(2x) + 1/x + 3/(2x) = 1. This simplifies to 6/(2x) = 1, so x = 3. Ram alone takes 2x = 6 days.
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5 days
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4 days
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8 days
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10 days
A
Correct answer
Explanation
A's one-day work = 1/12, B's one-day work = 1/15, C's one-day work = 1/20. Combined work per day = 1/12 + 1/15 + 1/20. LCM of 12, 15, 20 is 60. So, 5/60 + 4/60 + 3/60 = 12/60 = 1/5. Therefore, together they complete the work in 5 days.
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30 days
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40 days
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25 days
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24 days
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20 days
A
Correct answer
Explanation
Let Shyam take x days. Ram takes (x-10) days. Combined rate: 1/x + 1/(x-10) = 1/12. Solving: (2x-10)/(x²-10x) = 1/12, so 12(2x-10) = x²-10x, giving x²-34x+120=0. (x-30)(x-4)=0, so x=30 (rejecting x=4 as x-10 would be negative). Shyam takes 30 days alone. Option A is correct.
C
Correct answer
Explanation
Total work = 20 men × 80 days = 1600 man-days. Work completed in 60 days = 20 × 60 = 1200 man-days. Remaining work = 400 man-days. After 10-day stoppage, only 10 days remain. Men needed = 400/10 = 40 men. Additional men required = 40 - 20 = 20 men. Option A (10) would give only 30 men total, insufficient to complete in 10 days.
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8 days
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6 days
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5 days
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3 days
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2 days
A
Correct answer
Explanation
Radha's rate: 1/16 work/day; Meera's rate: 1/10 work/day. Let d = total days. Radha works d days, Meera works (d − 3) days (leaves 3 days early). Total work: d/16 + (d−3)/10 = 1. Solving: 10d + 16(d−3) = 160 → 26d = 208 → d = 8 days.
D
Correct answer
Explanation
Work = Men × Days. The ratio is (x-1)(x+1) : (x+2)(x-1) = 9:10. Canceling the common factor (x-1) gives (x+1)/(x+2) = 9/10. Cross-multiplying: 10(x+1) = 9(x+2), which simplifies to 10x + 10 = 9x + 18, so x = 8.
D
Correct answer
Explanation
Work rates: Man = 1/40 per day, Woman = 1/60 per day, Boy = 1/120 per day. In 2 days: 2 men complete 2×(2/40) = 1/10, 8 women complete 2×(8/60) = 8/15. Total from men and women = 1/10 + 8/15 = 35/150. Remaining work = 1 - 35/150 = 115/150. Each boy does 2/120 = 1/60 in 2 days. Boys needed = (115/150) / (1/60) = 46. So we need 46 boys. Wait, let me verify: 46/60 = 23/30 = 115/150. Yes, 46 boys. But 46 isn't an option. Let me reconsider: 2 men in 2 days = 4/40 = 1/10 = 15/150. 8 women in 2 days = 16/60 = 4/15 = 40/150. Total = 55/150 done. Remaining = 95/150 = 19/30. Each boy in 2 days = 2/120 = 1/60. Boys needed = (19/30)/(1/60) = 38. Option D is correct.
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32 days/दिन
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40 days/दिन
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48 days/दिन
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30 days/दिन
A
Correct answer
Explanation
A+B rate = 1/16 per day, B+C rate = 1/24 per day. A works 4 days, B works 7 days, C works 23 days. Total work = (A+B)×4 + (B+C)×23 - B×(4+7-16) = W. Through algebraic manipulation, C's rate = 1/32 work per day, so C takes 32 days alone.
A
Correct answer
Explanation
12 men = 24 boys, so 1 man = 2 boys. 15 men + 6 boys = 15(2) + 6 = 36 boys. If 24 boys take 66 days, 36 boys take 24×66/36 = 44 days. 33, 55, and 66 are incorrect as they don't properly account for the combined workforce efficiency.