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- Question
- A and B can do a piece of work in 9 days and 18 days, respectively. As they were ill, they could do 90% and 72% of their efficiency, respectively. How many days will they take to complete the work together?
Options- A. 71/7
- B. 8
- C. 5
- D. 121/2
- Correct Answer
- 71/7
ExplanationBecause of illness,
A's 1 day's work = 90% of 1/9 = 1/10
B's 1 day's work = 72% of 1/18 = 1/25
? (A + B)'s 1 day's work
= (1/10) + (1/25) = (5 + 2)/50 = 7/50
Hence, time taken by them to complete the work = 50/7 days
= 71/7 - 1. A, Band C can do a piece of work individually in 8, 12 and 15 days, respectively. A and B start working but A quits after working for 2 days. After this, C joins B till the completion of work. In how many days will the work be completed?
Options- A. 58/9 days
- B. 46/7 days
- C. 67/13 days
- D. 33/4 days Discuss
- 2. 90 men are engaged to do piece of work in 40 days but it is found that in 25 days, 2/3 work is complete. How many men should be allowed to go off, so that the work finished in time?
Options- A. 10
- B. 15
- C. 20
- D. 25 Discuss
- 3. 20 workers working for 5 h per day complete a work in 10 days. If 25 workers are employed to work 10 h per days, what is the time required to complete the work?
Options- A. 4 days
- B. 5 days
- C. 6 days
- D. 8 days Discuss
- 4. A and B can complete a job in the 24 days working together. A alone can complete it in 32 days. Both of them worked together for 8 days and then A left. The number of days B will take to complete the remaining job is
Options- A. 16
- B. 32
- C. 64
- D. 128 Discuss
- 5. A and B together can complete a work in 3 days. They started together but after 2 days, B left the work. If the work is completed after 2 more days, B alone could do the work in how many days?
Options- A. 5
- B. 6
- C. 7
- D. 10 Discuss
- 6. 36 workmen are employed to finish a certain work in 48 days. But it is found that in 24 days only 2/5 work is done. How many more men must be employed to finish the work in this?
Options- A. 16
- B. 18
- C. 20
- D. 22 Discuss
- 7. It is given that 16 men working 18 h a day can build a wall 36 m long, 4 m broad and 24 m high in 20 days. How many men will be required to build a wall 64 m long, 6 m broad and 18 m high working 12 h a day in 16 days?
Options- A. 60
- B. 20
- C. 30
- D. 35 Discuss
- 8. A men can do a piece of work in 5 days. With the help of his friend, he can do the same work in 3 days. In how many days can his friend complete the work?
Options- A. 6 days
- B. 61/2 days
- C. 7 days
- D. 71/2 Discuss
- 9. A and B each working alone can do a work in 15 days and 25 days, respectively. They started the work together but B left after some time and A finished the remaining work in 7 days. After how many days from the start did B leave?
Options- A. 3
- B. 5
- C. 7
- D. 9 Discuss
- 10. A can complete a work in 20 days and B in 30 days. A worked alone for 4 days and then B complete the remaining work alone with C in 18 days. In how many days can C working alone complete the work?
Options- A. 12
- B. 68
- C. 72
- D. 90 Discuss
Time and Work problems
Search Results
Correct Answer: 58/9 days
Explanation:
Work done by A and B in 1 day
= (1/8) + (1/12) = 5/24
2 day's work of A and B = 10/24
After 2 day's A left the work
? Remaining work = 1 - (10/24) = 14/24
One day work of B and C together = (1/12) + (1/15) = 9/60
So, the number of days required by B and C to finish work
= (14/24) / (9/60) = (14/24) x (60/9) = 35/9
? Total days to complete the work = 2 + (35/9) = 53/9 = 58/9 days
Correct Answer: 15
Explanation:
Let N men are allowed to go off,
M1= 90, D1 = 25, D2 = 15
W1 = 2/3, W2 = 1 - (2/3) = 1/3
M2 = 90 - N
According to the formula, M1D1W2 = M2D2W1
? (90 x 25) (1/3) = (90 - N) x 15 x (2/3)
? 90 x 25 x (1/3) = 10(90 - N)
? 75 = 90 - N
? N = 90 - 75 = 15
Correct Answer: 4 days
Explanation:
Given, M1= 20, M2 = 25, T1 = 5, T2 = 10, D1 = 10 and D2 = ?
According to the formula,
M1T1D1= M2T2D2
? 20 x 5 x 10 = 25 x 10 x D2
? D2 = 20 x 5 x 10/25 x 10 = 4 days
Correct Answer: 64
Explanation:
Let B will take N days to complete the remaining job.
According to the question
(1/A) + (1/B) = 1/24 and 1/A = 1/32
? 1/B = (1/24) - (1/32) = 1/96
? B = 96 days
According to the question,
8[(1/A) + (1/B)] + N x (1/B) = 1
? 8 x (1/24) + (N/96) = 1
? (1/3) + (N/96) = 1
? N/96 = 1 -1/3
? N = (2 x 96)/3 = 64
Hence, B complete the remaining job in 64 days
Correct Answer: 6
Explanation:
(A + B)'s 2 day's work = 2 x (1/3) = 2/3
Remaining work = 1 - (2/3) = 1/3
A will complete 1/3 work in 2
A will complete 1 work in 6
A's 1 days work = 1/6
B's 1 day's work = (1/3) - (1/6) = 1/6
? B will take 6 days to complete the work alone.
Correct Answer: 18
Explanation:
Let N men are employed.
Given, M1 = 36, M2 = 36 + N, D1 = 24,
D2 = 24, W1 = 2/5, W2 = 1 - 2/5 = 3/5
According to the formula M1D1W2 = M2D2W1
? 36 x 24 x (3/5) = (36 + N) x 24 x (2/5)
? 36 x 3 = 2(36 + N) ? 108 = 72 + 2N
? N = 36/2 = 18 men
Correct Answer: 60
Explanation:
Given, M1 = 16, T1 = 18,
W1 = 36 x 4 x 24, D1 = 20 and M2 = ?
T2 = 12, W2 = 64 x 6 x 18, D2 = 16
According to the formula,
M1D1T1/ W1 = M2D2T2/ W2
? 16 x 20 x (18/36) x 4 x 24 = M2 x 12 x (16/64) x 6 x 18
? (15/36) x 24 = M2 x (2/64) x 6 x 18
? M2 = 60 men
Correct Answer: 71/2
Explanation:
(Man and his friend)'s 1 day's work = 1/3
Men's 1 day's work = 1/5
His friend's 1 day's work is = 1/3 - 1/5 = 2/15
Hence, his friend can complete the work in 15/2 = 71/2
Correct Answer: 5
Explanation:
Let B left work after N days from the start.
According to the question,
N/25 + (N + 7)/15 = 1
? (3N + 5N + 35) / 75 = 1
? 8N = 75 - 35
? N = 40/8
? N = 5
Correct Answer: 90
Explanation:
Work done by A in 4 days = 4/20 = 1/5
? Remaining work = 1 - 1/5 = 4/5
Let C can working alone complete the work in N days .
According to the question,
18/30 + 18/N = 4/5
? 18(N + 30) x 5 = 4 x 30 x N
? 90N + 2700 = 120N
? 30N = 2700
? N = 90 days
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