All questions of Time and Work for Civil Engineering (CE) Exam

A and B together can do a piece of work in 24 days, which B and C together can do it in 32 days. After A has been working at it for 10 days and B for 14 days, C finishes it in 26 days. In how many days C alone will do the work?
  • a)
    32
  • b)
    36
  • c)
    44
  • d)
    48
  • e)
    None of these
Correct answer is option 'D'. Can you explain this answer?

Anaya Patel answered
Correct Answer :- d
Explanation : Work done by (A+B)'s in 1 day = 24
work done by (B+C)'s in 1 day = 32
Let C does a work in x days
Then work done by C in a day = 1/x
According to the question
A's 10 day's work + B's 14 day's work + C's 26 day's work = 1
10A + 14B + 26C = 1 ;
10A + 10B + 4B + 4C + 22C = 1 ;
10(A + B ) + 4( B + C ) + 22C = 1 ;
10( 1/24 ) + 4( 1/32 ) + 22C = 1 ;
10/24 + 4/32 + 22C = 1 ;
13/24 + 22C = 1 ;
22C = 1 - 13/24 ;
22C = 11/24 ;
2C = 1/24 ;
C = 1/48 ;
Therefore , C alone takes 48 days to finish the job.

If P can do 1/3 of the work in 5 days and Q can do 1/4 of the work in 6 days, then how much money will Q get if they were paid a total of 390 rupee?
  • a)
    120
  • b)
    150
  • c)
    170
  • d)
    190
  • e)
    None of these
Correct answer is option 'B'. Can you explain this answer?

sol = P can alone complete the whole work in 15 days and Q can complete the same work alone in 24 days. So ratio of work done by them 1/15: 1/24 i.e. 8: 5
Q get = (5/13)*390 = 150

Arun can do a certain work in the same time in which Bipasha and Rahul together can do it. If Arun and Bipasha together could do it in 10 days and Rahul alone in 50 days, then Bipasha alone could do it in:
  • a)
    15 days
  • b)
    20 days
  • c)
    25 days
  • d)
    30 days
  • e)
    35 days
Correct answer is option 'C'. Can you explain this answer?

Kavya Saxena answered
Arun, Bipasha and rahul’s 1 day work = 1/10 + 1/50 = 6/50 = 3/25
Arun’s 1 day work = Bipasha + Rahul ‘s 1 day work
2*(Arun’s 1 day work) = 3/25
Arun’s 1 day work = 3/50
Bipasha’s 1 day work = 1/10 – 3/50 = 2/50 = 1/25

Efficiency of A is 25% more then B and B takes 25 days to complete a piece of work. A started a work alone and then B joined her 5 days before actual completion of the work. For how many days A worked alone?
  • a)
    9
  • b)
    11
  • c)
    10
  • d)
    25
  • e)
    12
Correct answer is option 'B'. Can you explain this answer?

Efficiency (A : B) = 5 : 4
Number of days(A : B) = 4x : 5x = 4x : 25
∴ Number of days required by A to finish the work alone = 4x
= 4 x 5 = 20.
A and B work together for last 5 days = 5 x 9 = 45%
Efficiency of A = 5% and B’s efficiency = 4%
∴ No. of days taken by A to complete 55% work = 55/5 = 11days

Sekar, Pradeep and Sandeep can do a piece of work in 15 days. After all the three worked for 2 days, sekar left. Pradeep and Sandeep worked for 10 more days and Pradeep left. Sandeep worked for another 40 days and completed the work. In how many days can sekar alone complete the work if sandeep can complete it in 75 days?
  • a)
    25 days
  • b)
    20 days
  • c)
    30 days
  • d)
    35 days
  • e)
    15 days
Correct answer is option 'C'. Can you explain this answer?

Assume the total work to be 600 units. (LCM of all the numbers) Then Sandeep’s 1 day work = 8 units.
All three’s 1 day work = 40 units.All work together in the first 2 days
Work done in the first 2 days = 40 × 2 = 80 units
Sandeep alone works during the last 40 days
Work done in the last 40 days = 40 × 8 = 320 units
Remaining work = 600 – (320 + 80) = 200 units
This work is done by pradeep and sandeep in 10 days.
Pradeep and Sandeep together’s 1 day work = 20 units
Sekar’s 1 day work = All three 1 day work – Pradeep and Sandeep together’s 1 day
work = 40 units – 20 units = 20 units
Sekar can do the work of 600 units in 30 days.

Sruthi, Swetha and Swati together can cut 216 Apples of the same size in 3 hours. Number of Apples cut by Sruthi in 9 hours is same as the number of Apples cut by Swati in 7 hours. In one hour, Swati can cut as many Apples more than Swetha as Swetha can cut more than Sruthi.Then the number of Apples cut by Swetha in one hour?
  • a)
    21
  • b)
    24
  • c)
    27
  • d)
    29
  • e)
    None
Correct answer is option 'B'. Can you explain this answer?

Aruna Singh answered
 
Let's denote:
  • Sruthi's efficiency as 'S' apples/hour
  • Swetha's efficiency as 'W' apples/hour
  • Swati's efficiency as 'T' apples/hour
Given information:
  1. S * 9 = T * 7 => S = (7/9)T
  2. T - W = W - S => T = 2W - S
Total work done in 3 hours:
  • (S + W + T) * 3 = 216
  • S + W + T = 72
Substituting S and T in terms of W:
  • (7/9)T + W + 2W - (7/9)T = 72
  • 3W = 72
  • W = 24
Therefore, Swetha can cut 24 apples in one hour.
So, the correct answer is option B: 24.

A, B and C are three friends that take 20 days to finish a work. The time taken by B is twice the time taken by A and C together and time taken by C to do the work is thrice the time taken by A and B together. How much time will be taken by A alone to do the work.
  • a)
    42 days
  • b)
    44 days
  • c)
    46 days
  • d)
    48 days
  • e)
    None of these
Correct answer is option 'D'. Can you explain this answer?

Nikita Singh answered
1/a + 1/b + 1/c = 1/20 (given)
In first case let time taken by A and C together is p days, then the time taken by B will be 2p. Substitute in the above equation and we get p = 60 (time taken by B to complete the work).
Similarly in the second case, u will get P = 80 (time taken by C to complete the work)
Now, 1/a = 1/20 – 1/60 – 1/80 to get the answer

Ramu, Hari and Sanjay are three typists, who working simultaneously, can type 228 pages in four hours. In one hour, Sanjay can type as many pages more than Hari as Hari can type more than Ramu. During a period of five hours, Sanjay can type as many passages as Ramu can, during seven hours. How many pages does each of them type per hour?
  • a)
    16, 18, 22
  • b)
    14, 17, 20
  • c)
    15, 17, 22
  • d)
    15, 18, 21
  • e)
    16, 19, 22
Correct answer is option 'E'. Can you explain this answer?

Let Rohit, Harsh and Sanjeev can type x, y and z pages respectively in 1 h. Therefore, they together can type 4(x + y + z) pages in 4 h
∴ 4(x + y + z) = 228
⇒ x + y + z = 57 …..(i)
Also, z – y = y – x
i.e., 2y = x + z ……(ii)
5z = 7x ……(iii)
From Eqs. (i) and (ii), we get
3y = 57
⇒ y = 19
From Eq. (ii), x + z = 38
x = 16 and z = 22

A does half as much work as B does in one sixth of the time. If together they take 20 days to complete the work, then what is the time taken by B to complete the work independently.
  • a)
    80 days
  • b)
    100 days
  • c)
    120 days
  • d)
    140 days
  • e)
    None of these
Correct answer is option 'A'. Can you explain this answer?

Ravi Singh answered
Let B take X days to complete the work then in one –sixth of the time i.e. x/6 days. Now A do half work as done by B so A will take twice the time i.e. 2*x/6 = x/3 to complete the job alone
So 1/x + 3/x = 1/20, x = 80 days

When Ashok and Karthik are working alone, they can complete a piece of work in 25 days and 30 days respectively. On day 1, Karthik started the work and Ashok joined B from day 3 on-wards. Find approximately after how many days will the work be completed?
  • a)
    20 days
  • b)
    10 days
  • c)
    15 days
  • d)
    25 days
  • e)
    30 days
Correct answer is option 'C'. Can you explain this answer?

Aisha Gupta answered
Fraction of work completed by Karthik on day 1 and day 2 = 2* 1/30 = 1/15
Fraction of work left after 2 days = 14/15
Fraction of work completed by Both = 1/25 + 1/30 = 11/150
Number of days after day 2 to complete work = 14*150/15*11 = 13 days
So after 2+13 = 15 days works will be completed

Angel can do a piece of work in 10 days, Balu in 15 days. They work together for 5 days, the rest of the work is finished by Chitra in two more days. If they get Rs. 6000 as wages for the whole work, what are the daily wages of Angel, Bala and Chitra respectively?
  • a)
    200, 250, 300
  • b)
    300, 200, 250
  • c)
    600, 400, 200
  • d)
    600, 400, 500
  • e)
    None of these
Correct answer is option 'D'. Can you explain this answer?

Angel’s 5 days work = 50%
Balu’s 5 days work = 33.33%
Chitra’s 2 days work = 16.66%
[100- (50+33.33)]
Ratio of work of Angel, Balu and Chitra = 3: 2: 1
Angel’s total share = Rs. 3000
Balu’s total share = Rs. 2000
Chitra’s total share = Rs. 1000
Angel’s one day’s wage = Rs.600
Balu’s one day’s wage = Rs.400
Chitra’s one day’s wage = Rs.500

Ravi can do a piece of work in 16 days. Rakesh can do the same work in 64/5 days, while Geeta can do it in 32 days. All of them started to work together but Ravi leaves after 4 days. Rakesh leaves the job 3 days before the completion of the work. How long would the work last?
  • a)
    6 days
  • b)
    9 days
  • c)
    18 days
  • d)
    5 days
  • e)
    None of these
Correct answer is option 'B'. Can you explain this answer?

Kavya Saxena answered
Let the work lasted for x days,
Ravi’s 4 day’s work + Rakesh (x – 3) day’s work + Geeta’s x day’s work = 1
⇒ (4/16) + (x – 3) / (64/5) + x/32 = 1
⇒ 5(x – 3)/64 + x/32 = 1 – 1/4
⇒ [5(x – 3) + 2x] / 64 = 3/4
⇒ 7x – 15 = 48
∴ x = (48 + 15)/7 = 63/7 = 9 days

A piece of work has to be completed in 50 days, a number of men are employed but it is found that only half of the work is done in 30 days, then an additional 20 men were joined to complete the work on time. How many men initially put to work?
  • a)
    30
  • b)
    35
  • c)
    40
  • d)
    45
  • e)
    None of these
Correct answer is option 'C'. Can you explain this answer?

Sagar Sharma answered
Given information:
- Total work has to be completed in 50 days
- Only half of the work is done in 30 days
- An additional 20 men were joined to complete the work on time

Let the total work be represented by W.

Work done in 30 days:
- In 30 days, only half of the work is done
- Work done = 0.5W

Work done by initial men in 30 days:
- Let x be the number of men initially put to work
- Work done by x men in 30 days = 30 * x
- Since only half of the work is done, 30 * x = 0.5W
- x = 0.5W / 30 = W / 60

Work done by additional men in 20 days:
- An additional 20 men were joined to complete the work on time
- Total men working = x + 20 = W / 60 + 20
- Work done by (W / 60 + 20) men in 20 days = 20 * (W / 60 + 20) = W

Equating the work done:
- 20 * (W / 60 + 20) = W
- 20W / 60 + 400 = W
- 20W + 24000 = 60W
- 40W = 24000
- W = 600

Calculating the number of men initially put to work:
- x = W / 60 = 600 / 60 = 10

Therefore, the number of men initially put to work is 40. So, option (c) is correct.

A does half as much work as B does in one sixth of the time. If together they take 20 days to complete the work, then what is the time taken by A to complete the work independently.
  • a)
    80/3 days
  • b)
    100/3 days
  • c)
    60/3 days
  • d)
    140/3 days
  • e)
    None of these
Correct answer is option 'A'. Can you explain this answer?

Faizan Khan answered
Let B complete the work in X days so in one day work done by B is 1/x
as A do half work in one-sixth of the time so A will complete work in 2*x/6 = x/3 days
One day work of A and B i.e. 3/x + 1/x = 1/20. So we get x = 80
So time taken by A alone = 80/3 days

Madhavan can finish a work in 5 hours. He invites Manohar and Manjima who can work 3/4th as fast as he can to join him. He also invites Mani and Mohan who can work only 1/5th as fast as he can to join him. If the five person team works the same job and they start together, how long will it take for them to finish the job?
  • a)
    50/97 days
  • b)
    87 days
  • c)
    50/29 days
  • d)
    78 days
  • e)
    62 days
Correct answer is option 'C'. Can you explain this answer?

Anaya Patel answered
Let the work be 100 units.
Madhavan’s 1 hour work = 100/5 = 20 units
Manohar and Manjima’s 1 day work = 3/4 × 20 = 15 units.
Mohan and Mani’s 1 day work = 1/5 × 20 = 4 units.
In one day all five of them can do = 20 + 15 + 15 + 4 + 4 = 58 units of work. Hence they can complete the work in 100/58 days.

A building contractor undertook to finish a certain work in 162 days and employed 150 men. After 72 days, he found that he had already done 2/3 of the work. How many men can be discharged now, so that the work finish in time?
  • a)
    80
  • b)
    75
  • c)
    90
  • d)
    70
  • e)
    65
Correct answer is option 'C'. Can you explain this answer?

Rajeev Kumar answered
M1 = 150, M2 = 150 – n, D1 = 72, D2 = 90
W1= 2/3 and W2 = 1/3
According to the formula,
(M1D1) / W1 = (M2D2) / W2
⇒ [150 x 72] / 2 = [(150 – n) x 90] / 1
⇒ (150 x 72) / (2 x 60) = (150 – n)
⇒ (150 – n) = 60
∴ n = 150 – 60 = 90

Gopal does a work in 90 days, Vikash in 40 days and Santhosh in 12 days. They work one after another for a day each, starting with Gopal followed by Vikash and then by Santhosh. If the total wages received are Rs 360 and Gopal, Vikash, Santhosh share them in the ratio of the work done, find their respective individual wages.
  • a)
    Rs 44, Rs 80 and Rs 264
  • b)
    Rs 40, Rs 87 and Rs 276
  • c)
    Rs 36, Rs 81 and Rs 243
  • d)
    Rs 42, Rs 86 and Rs 232
  • e)
    Rs 37, Rs 89 and Rs 284
Correct answer is option 'C'. Can you explain this answer?

Rajeev Kumar answered
Assume there are 360 units of work (LCM of 90, 40 and 12).
Hence, they can do 4,9 and 30 units per day or together 43 units every 3 days.
So In 24 days, 43×8=344 units of work is completed.
In the next 2 days, 13 unitsare completed and on 27th day,Santhosh takes 1/10 thof a day to finish the rest.
So, gopal and vikash worked for 9 days each and have hence put in 36 and 81 units respectively, and the rest of the 243 units is put in by santhosh.
The wages shall also be distributed in the same ratio as: Rs 36, Rs 81 and Rs 243.

A, B and C together can complete a work in 8 days. If A is 50% more efficient than B and B is 50% less efficient than C, then B alone will complete the same work in:
  • a)
    16 days
  • b)
    24 days
  • c)
    48 days
  • d)
    36 days
  • e)
    None of these
Correct answer is option 'D'. Can you explain this answer?

EduRev GATE answered
Let the efficiency of C be 10 units a day.
B's efficiency = 10 - 10 × 50% = 5 units
A's efficiency = 5 + 5 × 50% = 7.5 units
So, the total work = 8 × (10 + 5 + 7.5)
⇒ 8 × 22.5 = 180 units
Now, B alone will complete the work in = 180/5
⇒ 36 days
∴ B alone will complete the work in 36 days.

If 4 boys or 5 women can reap a field in 20 days. Then what will be the time taken by 6 boys and 8 women to reap the field.
  • a)
    200/33 days
  • b)
    200/31 days
  • c)
    200/35 days
  • d)
    200/37 days
  • e)
    None of these
Correct answer is option 'B'. Can you explain this answer?

Kavya Saxena answered
work done by one boy in one day = 1/(4*20) Similarly for women = 1/(5*20) Now the time taken by 6 boys and 8 women to reap the field = 6/80 + 8/100 = 1/d (d = 200/31 will be the answer)

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