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

After working for 6 days, Ashok finds that only 1/3 rd of the work has been done. He employs Ravi who is 60% as efficient as Ashok. How many days more would Ravi take to complete the work?

  1. 20 days

  2. 19 days

  3. 12 days

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

Ashok does 1/3 work in 6 days, so he does 1/18 work per day. Ravi is 60% as efficient, so Ravi does 0.6 * (1/18) = 1/30 work per day. Remaining work is 2/3. Days for Ravi = (2/3) / (1/30) = 20 days.

Multiple choice

Two men and three women working 7 hours a day finish a work in 5 days. Four men and four women working 3 hours a day complete the work in 7 days. The number of days in which only 7 men working 4 hours a day will finish the work is?

  1. 6 days

  2. 7 days

  3. 5 days

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

Work = (2M + 3W) * 7 * 5 = 70M + 105W. Also Work = (4M + 4W) * 3 * 7 = 84M + 84W. Equating: 70M + 105W = 84M + 84W => 21W = 14M => 3W = 2M. Total work = 70M + 105(2/3 M) = 70M + 70M = 140M. 7 men working 4 hours/day: 140M / (7M * 4) = 140/28 = 5 days.

Multiple choice

If A and B can finish a work in 10 days, B and C can finish the same work in 12 days, C and A can finish the same work in 15 days; then in how many days can A, B and C together finish half of the work?

  1. 8 days

  2. 5 days

  3. 4 days

  4. 3 days
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let the work be 60 units. A+B=6 units/day, B+C=5 units/day, C+A=4 units/day. Adding these gives 2(A+B+C) = 15 units/day, so A+B+C = 7.5 units/day. To finish half the work (30 units), they need 30 / 7.5 = 4 days.

Multiple choice

Prakash, Qasim, and Raunak can complete a task in 54 days together. Prakash and Qasim together can complete three times the work that Raunak can do in a day. Prakash and Raunak together can complete four times the work that Qasim can do in a day. Find the number of days it takes for Raunak to complete the work alone.

  1. 96 days

  2. 120 days

  3. 108 days

  4. 216 days
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Let P, Q, R be work rates. P+Q+R = 1/54. P+Q = 3R. P+R = 4Q. From P+Q=3R, substitute into first: 3R+R = 1/54 => 4R = 1/54 => R = 1/216. Raunak takes 216 days.

Multiple choice

Three individuals, Alice, Bob, and Carol, respectively take 25 days, 40 days, and 50 days to complete a project. How many days will it take for Alice to complete the project if she is assisted by Bob and Carol every second day?

  1. 14 days

  2. 16 days

  3. 18 days

  4. 20 days

  5. a
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Alice's rate = 1/25. Bob's rate = 1/40. Carol's rate = 1/50. Combined rate (Alice+Bob+Carol) = (8+5+4)/200 = 17/200. Every two days, the work done is (1/25) + (17/200) = (8+17)/200 = 25/200 = 1/8. To complete 1 project, it takes 8 cycles of 2 days = 16 days.

Multiple choice

8 girls and 12 boys can complete a work in 4 days. If one boy alone completes the work in 60 days, then in how many days a girl will be able to finish the same work alone?

  1. 150

  2. 140

  3. 160

  4. 144

  5. 156
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

1 boy takes 60 days, so 1 boy's 1-day work = 1/60. 12 boys' 1-day work = 12/60 = 1/5. 8 girls + 12 boys take 4 days, so (8G + 12B) 1-day work = 1/4. 8G + 1/5 = 1/4. 8G = 1/4 - 1/5 = 1/20. 1G = 1/160. A girl takes 160 days.