Quantitative Aptitude

Time and Work

2,195 Questions
All Pairwise rates and staged schedules 440 Workers-days-hours chain rule 439 LCM units and efficiency ratios 409 Different worker categories 311 Combined rates and an unknown worker 257 Division of wages 219 Alternate work 110 Opposing rates 10

Time and Work Questions

Multiple choice general knowledge math & puzzles

A painting job can be completed by 3 painters in 29 days. If 6 more painters join the team 2 days after starting work on the job, then how many more days are required to complete the job?

  1. 7

  2. 8

  3. 9

  4. 10
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Total work = 3 painters × 29 days = 87 painter-days. After 2 days, 6 painter-days are done, leaving 81 painter-days. With 9 painters (3 original + 6 new), remaining work takes 81/9 = 9 days. The question asks for additional days after day 2, so the answer is 9.

Multiple choice general knowledge math & puzzles

Ram, who is half as efficient as Krish, will take 24 days to complete a work if he worked alone. If Ram and Krish worked together, how long will they take to complete the work?

  1. 8

  2. 16

  3. 6

  4. 12
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Ram takes 24 days alone, so Ram's rate = 1/24 work/day. Krish is twice as efficient, so Krish's rate = 1/12 work/day. Together: 1/24 + 1/12 = 1/24 + 2/24 = 3/24 = 1/8 work/day. Time = 1/(1/8) = 8 days. Option B (16) is Ram's time alone - a common error of not combining rates.

Multiple choice general knowledge math & puzzles

15 men take 21 days of 8 hrs. each to do a piece of work. How many days of 6 hrs. each would it take for 21 women if 3 women do as much work as 2 men?

  1. 15

  2. 20

  3. 25

  4. 30
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

15 men × 21 days × 8 hours = 2520 man-hours total work. Since 3 women = 2 men, 1 woman = 2/3 man. 21 women = 21 × (2/3) = 14 men. Days needed = 2520 ÷ (14 × 6) = 2520 ÷ 84 = 30 days. Therefore 21 women working 6 hours daily would need 30 days to complete the same work.

Multiple choice general knowledge math & puzzles

A works thrice as much as B. If A takes 60 days less than B to do a work then find the number of days it would take to complete the work if both work together?

  1. 18.5 days

  2. 20.5 days

  3. 22.5 days

  4. 18 ways
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let B take x days, then A takes x/3 days. The difference is x - x/3 = 60, so 2x/3 = 60, meaning x = 90. B takes 90 days and A takes 30 days. Working together, their rate is (1/90 + 1/30) = 4/90. Days taken = 90/4 = 22.5 days.

Multiple choice general knowledge math & puzzles

If w workers, working at equal rates, can produce x toys in n days, how many days it takes c workers, working at same equal rates, to produce y toys?

  1. y*w*c/(w*n)

  2. y*w/(w*n*c)

  3. y*w*n / x

  4. y*w*n / (x*c)
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

To solve this question, the user needs to know the concept of the work rate formula, which is given by:

work = rate x time

where work refers to the amount of work done, rate refers to the rate at which work is done, and time refers to the amount of time taken to complete the work.

Using this formula, we can derive the formula for this question as follows:

work = rate x time

x = w*r*n (1) # The amount of work done by w workers in n days to produce x toys y = c*r*t (2) # The amount of work done by c workers in t days to produce y toys

Since the workers are working at the same rate, we can equate the rates in equations (1) and (2):

w*r = c*r

r = w*c/r

Substituting r in equation (1), we have:

x = w * (w*c/r) * n

x = w^2 * c * n / r

Substituting r in equation (2), we have:

y = c * (w*c/r) * t

y = w*c^2 * t / r

Equating the value of r in both equations, we get:

w*c/r = w*c/r

Thus, we can equate the two expressions for r and solve for t:

w*c/r = w*c/r

w*c/(w*c) = n/t

t = n*w*c/(w*c) = n

Therefore, the formula for the number of days it takes c workers to produce y toys is:

y = w^2 * c * n / x

Simplifying this expression, we get:

y*w*n / x*c

Therefore, the answer is:

The Answer is: D

Multiple choice general knowledge

Thirty men take 20 days to complete a job working 9 hours a day.How many hour a day should 40 men work to complete the job?

  1. 8 hrs

  2. 7 1/2 hrs

  3. 7 hrs

  4. 9 hrs
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Total work = 30 men × 20 days × 9 hours = 5400 man-hours. With 40 men: 5400/40 = 135 days total. Hours per day = 5400/(40×20) = 7.5 hours. The inverse proportion between men and hours (when days are constant) gives: (30×9)/40 = 7.5 hours per day.

Multiple choice general knowledge math & puzzles

A can complete a job in 20 days. B can do it in 30 days. A and B start working together and A leaves 10 days before the job is done. In how many days will the job be completed?

  1. 18

  2. 27

  3. 26.67

  4. 16
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let total days = d. A works for (d-10) days at rate 1/20 per day. B works for d days at rate 1/30 per day. Equation: (d-10)/20 + d/30 = 1. Solving: (3(d-10) + 2d)/60 = 1 → 5d-30 = 60 → 5d = 90 → d = 18. Check: A works 8 days (8/20 = 0.4), B works 18 days (18/30 = 0.6), total = 1 job.

Multiple choice general knowledge math & puzzles

Ben can have a piece of work done in 8 days, Joe can work three times faster than the Ben, Ram can work five times faster than Ben. How many days will they take to do the work together ?

  1. 3 days

  2. 9/8 days

  3. 8/9 days

  4. 4 days
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Ben's rate = 1/8 work per day. Joe is 3× faster: rate = 3/8 per day. Ram is 5× faster: rate = 5/8 per day. Combined rate = 1/8 + 3/8 + 5/8 = 9/8 work per day. Time = Work ÷ Rate = 1 ÷ (9/8) = 8/9 days. This is approximately 0.89 days or about 21.3 hours.

Multiple choice general knowledge math & puzzles

A is 50% more efficient than B. If B alone can do a piece of work in 24 days, in how many days A and B can together finish the same work?

  1. 9.6 Days

  2. 8 Days

  3. 6 Days

  4. 16 Days
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A's efficiency is 50% more than B, so A's rate = 1.5 × (1/24) = 1/16. Combined rate = 1/24 + 1/16 = 5/48 work per day. Days needed = 48/5 = 9.6 days. Option D (16 days) is B's time alone, option C (6 days) would require faster workers, and option B (8 days) is too low.