Quantitative Aptitude
Time and Work
2,195 Questions
Time and Work Questions
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Rs. 900
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Rs. 450
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Rs. 1200
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Rs. 500
B
Correct answer
Explanation
Let x be the wage for site 1 and y for site 2. 2x + 5y = 5400 and 4x + 9y = 9900. Multiplying the first by 2 gives 4x + 10y = 10800. Subtracting the second equation gives y = 900. Substituting back, 2x + 4500 = 5400, so 2x = 900, x = 450.
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Rs. 4500
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Rs. 6000
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Rs. 7500
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Rs. 3600
A
Correct answer
Explanation
Let x be the wage per day at site 1 and y be the wage per day at site 2. 2x + 5y = 5400 and 4x + 9y = 9900. Multiplying the first by 2 gives 4x + 10y = 10800. Subtracting the second from this gives y = 900. Then 2x + 5(900) = 5400, so 2x = 900, x = 450. Akash's wages: 4(450) + 3(900) = 1800 + 2700 = 4500.
C
Correct answer
Explanation
Using the work-man formula M1 * D1 = M2 * D2, we have 5 * 28 = X * 7. Thus, X = (5 * 28) / 7 = 5 * 4 = 20.
A
Correct answer
Explanation
Work = Men * Days. y = (x-1)(x+1) = x^2 - 1. z = (x+2)(x-1) = x^2 + x - 2. Ratio y/z = (x-1)(x+1) / ((x+2)(x-1)) = (x+1)/(x+2) = 9/10. 10x + 10 = 9x + 18. x = 8.
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5 days
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7 days
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8 days
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9 days
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11 days
B
Correct answer
Explanation
Let x be the days they worked together. (x/70 + x/60) + 47/60 = 1. (x/70 + x/60) = 13/60. x * (6+7)/420 = 13/60. x * 13/420 = 13/60. x = 420/60 = 7.
A
Correct answer
Explanation
Work done in 5 days by 20 men = 1/4. Remaining work = 3/4. Men required for 3/4 work in 5 days: (20 men * 5 days) / (1/4 work) = (M * 5 days) / (3/4 work). 20 * 5 * 4 = M * 5 * (4/3) -> M = 60. Additional men needed = 60 - 20 = 40.
B
Correct answer
Explanation
Work = men * days. x = (3n - 1)(2n + 1) = 6n^2 + n - 1. y = (3n + 1)(4n - 3) = 12n^2 - 5n - 3. x/y = 6/11. 11(6n^2 + n - 1) = 6(12n^2 - 5n - 3). 66n^2 + 11n - 11 = 72n^2 - 30n - 18. 6n^2 - 41n - 7 = 0. Solving for n: (6n + 1)(n - 7) = 0. n = 7.
C
Correct answer
Explanation
Let x be the days worked. Then (30-x) is the days absent. 500x - 100(30-x) = 11400. 500x - 3000 + 100x = 11400. 600x = 14400. x = 24.
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11th day
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13th day
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15th day
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18th day
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None of these
C
Correct answer
Explanation
X is 60% more efficient than Y, so X/Y = 160/100 = 8/5. If X takes 23 days, the total work is 8 * 23 = 184 units. Y's efficiency is 5 units/day. Together, they do 13 units/day. 184/13 is approximately 14.15, meaning they finish on the 15th day.
A
Correct answer
Explanation
Using the formula (M1 * D1 * H1) = (M2 * D2 * H2), we have (10 * 60 * 9) = (M2 * 30 * 5). Solving for M2 gives 5400 / 150 = 36 men. Since 10 men were already working, the additional men required is 36 - 10 = 26.
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4 days
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5 days
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7 days
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10 days
A
Correct answer
Explanation
If A is 25% as efficient as B, then B is 4 times as efficient as A. If A takes x days, B takes x/4 days. Given x = (x/4) + 15, we find 3x/4 = 15, so x = 20. A takes 20 days and B takes 5 days. Together, they take (20 * 5) / (20 + 5) = 100 / 25 = 4 days.
D
Correct answer
Explanation
Total work = 12 * 5 = 60 man-days. To finish in 3 days, we need 60 / 3 = 20 people. Additional people = 20 - 12 = 8.
C
Correct answer
Explanation
Let A and B take x and y days to complete the work. (1/3)x + (2/3)y = 40 and (2/3)x + (1/3)y = 35. Multiply by 3: x + 2y = 120 and 2x + y = 105. Solving gives x=30, y=45. Together: 1/(1/30 + 1/45) = 1/(3/90 + 2/90) = 90/5 = 18 days.