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- Question
- A and B can do a piece of work in 12 days, B and C can do it in 15 days and C and A can do the same work in 20 days. Find the number of days in which A alone can do the same job?
Options- A. 20 days
- B. 30 days
- C. 45 days
- D. 60 days
- Correct Answer
- 30 days
ExplanationWork done by A and B in one day = 1/12
Work done by B and C in one day = 1/15
Work done by C and A is one day = 1/20
On adding all these,
2(A + B + C)'s work of one day = 1/12 + 1/15 +1/20 = 1/5
? (A + B + C)'s one day work = 1/10
? A' s one day work = (A + B + C)'s one day work - (B + C )'s one day work
? A's one day work 1/10 - 1/15 = 1/30
Hence, A can do this work in 30 days. - 1. A leak in the bottom of a tank can empty the full tank in 6 h. An inlet pipe fills water at the rate of 4 L in a min. When the tank is full, the inlet is opened and due to the leak the tank is empty in 8 h. Find the capacity of the tank?
Options- A. 5000 L
- B. 5670 L
- C. 5700 L
- D. 5760 L Discuss
- 2. A man, a women and a boy can do a job in 3, 4 and 12 days , respectively. How many boys must assist one man and one women to complete the job in one and a half days?
Options- A. 12
- B. 6
- C. 3
- D. 1 Discuss
- 3. Pipes A and B can fill a tank in 20 h and 30 h, respectively and pipe C can empty the full tank in 40 h. If all the pipes are opened together, how much time will be needed to make the tank full?
Options- A. 161/7 h
- B. 171/7 h
- C. 181/7 h
- D. 191/7 h Discuss
- 4. A man is paid ? 5 per h for regular working day and ? 8 per h overtime. A regular working day has 8 h and a regular week has 5 working days. If he earns ? 920 in 4 weeks, then what is the total number of hours that he worked assuming that he was present on all regular working days?
Options- A. 200 h
- B. 180 h
- C. 175 h
- D. 160 h Discuss
- 5. The efficiency of Romil is twice that of Sanjay and he can finish a work in 4 h less than the time taken by Sanjay. If both of them work together they can finish the same work in?
Options- A. 8 h
- B. 3 h
- C. 8 / 3 h
- D. 4 / 3 h Discuss
- 6. Two friend A and B working together completed a work in 26 days. Their skills of doing the work are in the ratio 8 : 5. How many days will B take, if engaged alone?
Options- A. 673/5 days
- B. 421/4 days
- C. 563/5 days
- D. 642/3 days Discuss
- 7. A and B together can complete a piece of work in 35 days while A alone can complete the same work in 60 days. In how many days, B alone will be able to complete the same work?
Options- A. 80 days
- B. 84 days
- C. 88 days
- D. 92 days Discuss
- 8. A and B can do a piece of work in 72 days, B and C can do it in 120 days, A and C can do it in 90 days. In what time can A alone do it?
Options- A. 60 days
- B. 90 days
- C. 115 days
- D. 120 days Discuss
- 9. Ram finishes a work in 7 days. Rahim finish the same job in 8 days and Robert in 6 days. They take turns to finish the work. Ram worked on the first day, Rahim on the second day and Robert on the third and then again Ram and so on. Who was working on the last day when work got finished?
Options- A. Ram
- B. Rahim
- C. Robert
- D. Rahim and Robert Discuss
- 10. 12 men and 16 boys can do a piece of work in 5 days while 13 men and 24 boys finish it in 4 days. 5 men and 10 boys will finish it in?
Options- A. 10 days
- B. 12 days
- C. 9 days
- D. 15 days Discuss
Time and Work problems
Search Results
Correct Answer: 5760 L
Explanation:
Efficiency of the leak = 1/6
Combined efficiency of leak and inlet pipe
So, efficiency of inlet pipe = 1/6 - 1/8 = (4 - 3)/24 = 1/24
Inlet pipe can fill the tank in 24 h, at rate of 4 L/min.
? Capacity = 24 x 60 x 4 = 5760 L
Correct Answer: 1
Explanation:
Portion of work completed by one man in 11/2 days.
i.e., 3/2 days = 3/(2 x 3) = 1/2
Portion of work completed by one women in 11/2 days.
i.e., 3/2 days = 3/(2 x 4) = 3/8
? Portion of work completed by boys = 1 - (1/2 + 3/8) = 1/8
Now, portion of work completed by each boy in 3/2 days = 3/(2 x 12) = 1/8
Hence, only one boys would be required.
Correct Answer: 171/7 h
Explanation:
Net part filed in 1 h = (1/20 + 1/30 - 1/40) = 7/120
Hence, the tank will be full in 120/7 = 171/7 h
Correct Answer: 175 h
Explanation:
Number of regular hours during 4 weeks = 8 x 5 x 4 = 160
Amount paid for regular working hours = 160 x 5 = ? 800
Balance left = (920 - 800) = ? 120
So, ? 120 is paid for his over time at ? 8 per h.
? Total number of overtime working hours = 120/8 = 15 h
Total working hours = (160 + 15) = 175 h
Correct Answer: 8 / 3 h
Explanation:
As the efficience of Romil is twice that of Sanjay, Romil, will take x h for completeion of the work, when Sanjay is taking 2x h.
Given, 2x - x = 4
? x = 4
Hence, they take = 1/(1/4 + 1/8) = 8/3 h
Correct Answer: 673/5 days
Explanation:
Skill ratio of A and B = 8 : 5
So, the time taken by A and B 5W and 8W, respectively.
According to the question, 1/8W + 1/5W = 1/26
? W = (13 x 26)/40
Now, time taken by B is 8W = 8 x 13 x 26/40
= 673/5 days.
Correct Answer: 84 days
Explanation:
In this question, A and B did the work for 35 days to complete it. A can complete the work in 60 days.
So, A did/A can + B did/B can = 1
? 35/60 + 35/x = 1
? x = 84 days
Correct Answer: 120 days
Explanation:
Combined efficiency of A and B = 1/72 ....(i)
Combined efficiency of B and C = 1/120 ....(ii)
Combined efficiency of A and C = 1/90 ....(iii)
On adding Eqs. (i), (ii) and (iii), we get
2(A + B + C) = 1/72 + 1/120 + 1/90 = (5 + 3 + 4)/360
= 12 / 360 = 1 / 30
? A + B + C = 1/60 .....(iv)
i.e Combined efficiency is 1/60 or we can say together A, B and C can complete the work in 60 days.
On subtracting Eq. (ii)from Eq. (iv), we get
Efficiency of A = Combined efficiency of A, B and C - Combined efficiency of B and C
= 1/60 - 1/120 = 1/120
Hence, A alone can do it in 120 days
Correct Answer: Ram
Explanation:
Three day work or Ram, Rahim and Robert = 1/7 + 1/8 + 1/6
= (24 + 21 + 28)/168 = 73/168
Their six days work = (2 x 73)/168 = 146/168 = 73/84
Now, its Ram's turn to work on seventh day.
? 73/84 + 1/7 = 73 + 12/84 = 85/84 > 1
So, Ram will finish the work before the end of day.
Hence, Ram is working for the last day.
Correct Answer: 10 days
Explanation:
(12 men + 16 boys) can do a work in 5 days.
(60 men + 80 boys) can do a work in 1 day.
(13 men + 24 boys) can do a work in 4 days.
(52 men + 96 boys) can do a work in 1 day.
? 60 men + 80 boys = 52 men + 96 boys
8 men = 16 boys and 1 man = 2 boys
Now, 12 men + 16 boys = (12 x 2 + 16) boys
= 40 boys can do the work in 5 days
? 5 men + 10 boys = [5 x 2 + 10] boys
= 20 boys will take
= (40 x 5)/20 = 10 days
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