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- Question
- A and B can do a job together in 12 days. A is 2 time as efficient as B. In how many days can B alone complete the work?
Options- A. 36
- B. 12
- C. 18
- D. 9
- Correct Answer
- 36
ExplanationTime take by A to complete a work = N days
? Time taken by B to complete the same work = 2N days
According to the question,
(1/N) + (1/2N) = 1/12
? 3 / 2N = 1/12
? N = (3 x 12)/2 = 18
Time taken by B to complete the same work = 2N= 2 x 18 = 36 days - 1. A mason can build a tank in 12 h. After working for 6 h. he took the help of a boy and finished the work in another 5 h. The time that the boy will take alone to complete the work is?
Options- A. 30 h
- B. 45 h
- C. 60 h
- D. 64 h Discuss
- 2. A contractor undertook to do a certain piece of the work in 18 days. He employed certain number of men but 12 of them being absent from the very 1st day, the rest could finish the work in 30 days . Find the number of men originally employed.
Options- A. 40
- B. 15
- C. 45
- D. 30 Discuss
- 3. A can do a piece of work in 10 days, while B can do it in 6 days. B worked at it for 4 days. How long will A take to finish the remaining work?
Options- A. 31/3 days
- B. 32/3 days
- C. 32/5 days
- D. 35/7 Discuss
- 4. A and B can do a piece of work in 10 h. B and C do it in 15 h, while A and C take 12 h to complete the work. B independently can complete the work in
Options- A. 12 h
- B. 16 h
- C. 20 h
- D. 24 h Discuss
- 5. A can do a piece of the work in 10 days and B in 20 days. They begin together but A leaves 2 days before the completion of the work. The whole work will be done in?
Options- A. 8 days
- B. 7 2/3 days
- C. 7 days
- D. 6 days Discuss
- 6. A is thrice as good a workman as B and therefore is able to finish a job in 30 days less then B. How many days will they takes to finish the job working together?
Options- A. 101/4
- B. 113/4
- C. 111/4
- D. 111/3 Discuss
- 7. X can do 20% of a work in day, Y can do 25% of the same work in days and X, Y and Z together can do 50% of the same work in a day. How many per cert of work can be done by Z in day?
Options- A. 5%
- B. 10%
- C. 15%
- D. 20% Discuss
- 8. 4 men or 6 women or 10 children can paint a house in 5 days. The painting is given to a couple and their 5 sons. They finish the job in?
Options- A. 11/60 days
- B. 55/11 days
- C. 56/11 days
- D. 111/5 days Discuss
- 9. 4 goats or 6 sheep can graze a field in 50 days. 2 goats and 9 sheep can graze the field in?
Options- A. 100 days
- B. 75 days
- C. 50 days
- D. 25 days Discuss
- 10. If the work done by 8 men and 4 boys in 1 days is 7 times the work done by 1 man and 1 boy, then compare the work done by 1 man and 1 boy in 1 days?
Options- A. 1
- B. 2
- C. 3
- D. 1/2 Discuss
Time and Work problems
Search Results
Correct Answer: 60 h
Explanation:
Mason's 1 h work = 1/12
Mason's 6 h work = 6/12 = 1/2
Remaining work = 1 - (1/2) = 1/2
Remaining work can be finish in 5 h total work can be finished in 2 x 5 = 10 h.
(1/12) + (1/B) = (1/10)
? 1/B = (1/10) - (1/12) = 1/60
Boy can complete the work in 60 h.
Correct Answer: 30
Explanation:
Let the number of the men at the beginning = N
Given, M1 = N, M2 = N - 12, D1 = 18 and D2 = 30
According to the formula
M1D1 = M2D2
? N x 18 = (N - 12) x 30
? 3N = 5N - 60
? 2N = 60
? N = 30
Correct Answer: 31/3 days
Explanation:
B's 4 days work = (1/6) x 4 = 2/3
? Remaining work = 1 - (2/3) = 1/3
A's 1 day's work = 1/10
? 1/3 work is finished by A in
(10 x 1/3) = 31/3 days
Correct Answer: 24 h
Explanation:
A's and B,s 1 h work= 1/10
B's and C,s 1 h work = 1/15
and A's and C's 1 h work = 1/12
? A's B's and C's 1 h work
= (1/2) x [(1/10) + (1/15) + (1/12)] = (1/2) x (1/4) = 1/8
Hence B's work in 1 h = (1/8) - (1/12) = 1/24
? B independently can complete the work in 24 h.
Correct Answer: 8 days
Explanation:
Let the required days be x.
A works for (x - 2) days, while B work for x days.
According to the question
(x - 2)/10 + x/20 = 1
? 2x - 4 + x = 20
? 3x = 24
? x = 8 days
Correct Answer: 111/4
Explanation:
Let A takes x and B takes 3N days to finish the job.
According to the question,
3N - N = 30
? N = 30/2 = 15 days
? B's time to complete the work = 3N
= 3 x 15 = 45 days
? (A + B)'s 1 day's work
= (1/15) + (1/45) = (3 + 1)/45 = 4/45
? (A + B) will finish the work in 4/45 days
? Required time = 4/45 = 111/4
Correct Answer: 5%
Explanation:
Work done by (x + y + z) in 1 day
= 50% = 1/2
Work done by x in 1 days = 20% = 1/5
Work done by y in 1 days = 25% = 1/4
? Work done by z in 1 day
= (1/2) - (1/5) - (1/4)
= (10 - 4 - 5)/20
= 1/20 = 5%
Correct Answer: 55/11 days
Explanation:
4 men = 6 women = 10 children
? 1 man = 5/2 children
1 women = 5/3 children
Now, 1 couple + 5 children = 1 man + 1 women + 5 children
= (5/2) + (5/3) + 5 = 55/6 children
According to the formula
M1D1 = M2D2
? 10 x 5 = (55/6) x D2
? D2 = 60/11 days
= 55/11 days
Correct Answer: 25 days
Explanation:
Part of field grazed by 4 goats in 1 day = 1/50
Part of field grazed by 1 goat in 1 day = (1/50) x 4 = 1/200
? 4 g = 6 s [here, g = goats, and s = sheep]
? 1 s = (4/6) g = (2/3) g
Now, 2 g + 9 s = 2 g + 9 x (2/3) g
= 2 g + 6 g = 8 g
? 8 goats can graze the field in (1/8) / 200 = 25 days
Correct Answer: 3
Explanation:
Here, a1 = 8, b1 = 4, a2 = 1, b2 = 1 and n = 7
? Work done by 1 man/Work done by 1 boy = (nb2 - b1)/(a1 - na2)
= (7 x 1 - 4) / (8 - 7 x 1)
= 3
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