Time and work
Ten quantitative aptitude questions, each marked as you answer.
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A and B together can do a job in 18 days. A alone can do it in 27 days. In how many days can B alone do it?
Answer and working
Answer C
B’s one day = 1/18 − 1/27 = 1/54. B alone takes 54 days.
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Ramesh can finish a piece of work in 45 days and Suresh can finish it in 36 days. Working together, how long will they take?
Answer and working
Answer A
In one day they do 1/45 + 1/36 = 1/20 of the work. Time = 45 × 36 ÷ (45 + 36) = 20 days.
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Ramesh can finish a piece of work in 55 days and Suresh can finish it in 66 days. Working together, how long will they take?
Answer and working
Answer B
In one day they do 1/55 + 1/66 = 1/30 of the work. Time = 55 × 66 ÷ (55 + 66) = 30 days.
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Ramesh can finish a piece of work in 36 days and Suresh can finish it in 45 days. Working together, how long will they take?
Answer and working
Answer D
In one day they do 1/36 + 1/45 = 1/20 of the work. Time = 36 × 45 ÷ (36 + 45) = 20 days.
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Ramesh can finish a piece of work in 12 days and Suresh can finish it in 6 days. Working together, how long will they take?
Answer and working
Answer B
In one day they do 1/12 + 1/6 = 1/4 of the work. Time = 12 × 6 ÷ (12 + 6) = 4 days.
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A is three times as efficient as B. Together they finish a job in 33 days. How long would A take alone?
Answer and working
Answer C
If B does 1 unit a day, A does 3; together 4 units a day for 33 days = 132 units. A alone: 132 ÷ 3 = 44 days.
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A and B together can do a job in 16 days. A alone can do it in 24 days. In how many days can B alone do it?
Answer and working
Answer B
B’s one day = 1/16 − 1/24 = 1/48. B alone takes 48 days.
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Ramesh can finish a piece of work in 42 days and Suresh can finish it in 7 days. Working together, how long will they take?
Answer and working
Answer B
In one day they do 1/42 + 1/7 = 1/6 of the work. Time = 42 × 7 ÷ (42 + 7) = 6 days.
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A is three times as efficient as B. Together they finish a job in 30 days. How long would A take alone?
Answer and working
Answer D
If B does 1 unit a day, A does 3; together 4 units a day for 30 days = 120 units. A alone: 120 ÷ 3 = 40 days.
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A is three times as efficient as B. Together they finish a job in 18 days. How long would A take alone?
Answer and working
Answer C
If B does 1 unit a day, A does 3; together 4 units a day for 18 days = 72 units. A alone: 72 ÷ 3 = 24 days.
More quantitative aptitude: Percentages, Profit, loss and discount, Simple interest, Compound interest, Ratio and proportion, Averages.