Time and Work
- Shashi can do a piece of work in 20 days. Tanya is 25% more efficient than Shashi. The number of days taken by Tanya to do the same piece of work is :
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Time taken by Shashi in doing 1 work = 20 days
Tanya is 25% more efficient than Shashi.
∴ Time taken by Tanya= 100 × 20 = 16 days 125 Correct Option: B
Time taken by Shashi in doing 1 work = 20 days
Tanya is 25% more efficient than Shashi.
∴ Time taken by Tanya= 100 × 20 = 16 days 125
- If 10 people can do a job in 20 days, then 20 people with twice the efficiency can do the same job in
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In second case, the efficiency of a man is twice to that in the first case.
∴ M1D1 = 2 M2D2
⇒ 10 × 20 = 2 × 20 × D2⇒ D2 = 10 × 20 = 5 days 2 × 20 Correct Option: A
In second case, the efficiency of a man is twice to that in the first case.
∴ M1D1 = 2 M2D2
⇒ 10 × 20 = 2 × 20 × D2⇒ D2 = 10 × 20 = 5 days 2 × 20
- A works twice as fast as B. If B can complete a piece of work independently in 12 days, then what will be the number of days taken by A and B together to finish the work?
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A is twice efficient than B.
∴ Time taken by B = 12 days
⇒ Time taken by A = 6 days
∴ (A + B)’s 1 day’s work= 1 + 1 = 2 + 1 = 1 6 12 12 4
∴ Required time = 4 daysCorrect Option: A
A is twice efficient than B.
∴ Time taken by B = 12 days
⇒ Time taken by A = 6 days
∴ (A + B)’s 1 day’s work= 1 + 1 = 2 + 1 = 1 6 12 12 4
∴ Required time = 4 days
- A man does double the work done by a boy in the same time. The number of days that 3 men and 4 boys will take to finish a work which can be done by 10 men in 8 days is
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According to the question,
1 man ≡ 2 boys
∴ 3 men + 4 boys ≡ (3 + 2) men ≡ 5 men
∴ M1D1 = M2D2
⇒ 5 × D1 = 10 × 8⇒ D1 = 10 × 8 = 16 days 5 Correct Option: B
According to the question,
1 man ≡ 2 boys
∴ 3 men + 4 boys ≡ (3 + 2) men ≡ 5 men
∴ M1D1 = M2D2
⇒ 5 × D1 = 10 × 8⇒ D1 = 10 × 8 = 16 days 5
- A is twice as good as B and together they finish a piece of work in 16 days. The number of days taken by A alone to finish the work is
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A is twice as good as B.
∴ Time taken by A = x days
Time taken by B = 2x days
According to the question,1 + 1 = 1 x 2x 16 ⇒ 2 + 1 = 1 2x 16 ⇒ 3 = 1 2x 16
⇒ x = 3 × 8 = 24 daysCorrect Option: D
A is twice as good as B.
∴ Time taken by A = x days
Time taken by B = 2x days
According to the question,1 + 1 = 1 x 2x 16 ⇒ 2 + 1 = 1 2x 16 ⇒ 3 = 1 2x 16
⇒ x = 3 × 8 = 24 days