Daily Quiz
Quantitative Aptitude — Time & Work
← All Quizzes Home

Quantitative Aptitude — Time & Work

⏱
19 mins
Time
❓
25
Questions
🎓
1
Per Q

Read the following instructions carefully:

✡ Select Language / भाषा चुनें
You can change language during quiz too / परीक्षा के दौरान भी बदल सकते हैं
Quantitative Aptitude — Time & Work — Questions with Answers Open after you finish the quiz — all 25 questions, with answers and explanations.
Q1. A is twice as efficient as B. If A and B together can complete a piece of work in 18 days, in how many days can B alone complete the work?
  1. 27 days
  2. 36 days
  3. 54 days
  4. 45 days
Show answer
Answer: C. 54 days
Let the efficiency of B be 1 unit/day. Then the efficiency of A is 2 units/day. Combined efficiency of A and B = 2 + 1 = 3 units/day. Total work = Combined efficiency × Days = 3 units/day × 18 days = 54 units. Time taken by B alone = Total work / Efficiency of B = 54 units / 1 unit/day = 54 days.
Q2. A can do a piece of work in 15 days and B can do it in 20 days. If they work together for 4 days, what fraction of the work is left?
  1. 7/15
  2. 8/15
  3. 1/3
  4. 2/5
Show answer
Answer: B. 8/15
A's 1-day work = 1/15. B's 1-day work = 1/20. (A+B)'s 1-day work = 1/15 + 1/20 = (4+3)/60 = 7/60. Work done in 4 days = 4 × (7/60) = 7/15. Work left = 1 - 7/15 = 8/15.
Q3. P is 50% more efficient than Q. If Q can complete a work in 30 days, then in how many days will P and Q together complete the same work?
  1. 10 days
  2. 15 days
  3. 18 days
  4. 12 days
Show answer
Answer: D. 12 days
Let Q's efficiency be 100 units/day. Then P's efficiency = 100 + 50% of 100 = 150 units/day. Ratio of efficiencies P:Q = 150:100 = 3:2. Q completes the work in 30 days. Total work = Q's efficiency × Days = 2 units/day × 30 days = 60 units. Combined efficiency of P and Q = 3 + 2 = 5 units/day. Time taken by P and Q together = Total work / Combined efficiency = 60 units / 5 units/day = 12 days.
Q4. A, B and C can complete a work in 10, 12 and 15 days respectively. They start the work together. A leaves after 2 days. B and C continue. In how many days will the work be completed?
  1. 5 1/3 days
  2. 6 days
  3. 5 days
  4. 6 1/3 days
Show answer
Answer: A. 5 1/3 days
Total work = LCM(10, 12, 15) = 60 units. A's efficiency = 60/10 = 6 units/day. B's efficiency = 60/12 = 5 units/day. C's efficiency = 60/15 = 4 units/day. Combined efficiency of A, B, C = 6 + 5 + 4 = 15 units/day. Work done in first 2 days by A, B, C = 15 × 2 = 30 units. Remaining work = 60 - 30 = 30 units. After A leaves, B and C work together. Combined efficiency of B and C = 5 + 4 = 9 units/day. Time taken by B and C to complete remaining work = 30 / 9 = 10/3 days. Total time to complete the work = 2 days (A,B,C) + 10/3 days (B,C) = 2 + 10/3 = (6+10)/3 = 16/3 = 5 1/3 days.
Q5. A is thrice as good a workman as B and therefore is able to finish a piece of work in 60 days less than B. Find the time in which they can do it working together.
  1. 20 days
  2. 22.5 days
  3. 25 days
  4. 27.5 days
Show answer
Answer: B. 22.5 days
Efficiency ratio A:B = 3:1. Time taken ratio A:B = 1:3 (inverse of efficiency ratio). Let A take 'x' days and B take '3x' days. Given that A takes 60 days less than B, so 3x - x = 60. 2x = 60 => x = 30 days. So, A takes 30 days and B takes 3 × 30 = 90 days. Together, their 1-day work = 1/30 + 1/90 = (3+1)/90 = 4/90 = 2/45. Time taken by A and B together = 45/2 = 22.5 days.
Q6. 12 men can complete a work in 8 days. 16 women can complete the same work in 12 days. 16 men and 16 women work together for 2 days. How much work is left?
  1. 1/2
  2. 1/4
  3. 3/4
  4. 1/3
Show answer
Answer: A. 1/2
Total work = 12 men × 8 days = 96 man-days. Total work = 16 women × 12 days = 192 woman-days. Equating the total work: 96 man-days = 192 woman-days => 1 man = 2 women. Now, convert 16 men and 16 women into man-days equivalent: 16 men + 16 women = 16 men + (16/2) men = 16 men + 8 men = 24 men. Work done by 24 men in 2 days = 24 × 2 = 48 man-days. Total work = 96 man-days. Work left = Total work - Work done = 96 - 48 = 48 man-days. Fraction of work left = 48/96 = 1/2.
Q7. A and B together can do a piece of work in 12 days. B and C together can do it in 15 days. C and A together can do it in 20 days. In how many days can A alone complete the work?
  1. 20 days
  2. 24 days
  3. 36 days
  4. 30 days
Show answer
Answer: D. 30 days
1-day work of (A+B) = 1/12. 1-day work of (B+C) = 1/15. 1-day work of (C+A) = 1/20. Adding all three equations: 2(A+B+C)'s 1-day work = 1/12 + 1/15 + 1/20 = (5+4+3)/60 = 12/60 = 1/5. (A+B+C)'s 1-day work = 1/(5 × 2) = 1/10. To find A's 1-day work, subtract (B+C)'s 1-day work from (A+B+C)'s 1-day work: A's 1-day work = (A+B+C)'s 1-day work - (B+C)'s 1-day work = 1/10 - 1/15 = (3-2)/30 = 1/30. So, A alone can complete the work in 30 days.
Q8. A can do a work in 24 days. If B is 20% more efficient than A, then in how many days can B alone complete the same work?
  1. 18 days
  2. 22 days
  3. 25 days
  4. 20 days
Show answer
Answer: D. 20 days
A's 1-day work = 1/24. B is 20% more efficient than A, so B's efficiency = A's efficiency × (100+20)/100 = A's efficiency × 1.2. B's 1-day work = (1/24) × 1.2 = (1/24) × (12/10) = (1/24) × (6/5) = 1/(4 × 5) = 1/20. So, B alone can complete the work in 20 days.
Q9. A, B and C can complete a work in 20, 30 and 60 days respectively. They all start the work together, and A leaves after 4 days. Then B also leaves after another 2 days. In how many days will C complete the remaining work?
  1. 20 days
  2. 25 days
  3. 30 days
  4. 35 days
Show answer
Answer: C. 30 days
Total work = LCM(20, 30, 60) = 60 units. A's efficiency = 60/20 = 3 units/day. B's efficiency = 60/30 = 2 units/day. C's efficiency = 60/60 = 1 unit/day. Combined efficiency of A, B, C = 3 + 2 + 1 = 6 units/day. Work done in first 4 days by A, B, C = 6 × 4 = 24 units. Remaining work = 60 - 24 = 36 units. After A leaves, B and C work together. Combined efficiency of B and C = 2 + 1 = 3 units/day. Work done in next 2 days by B and C = 3 × 2 = 6 units. Remaining work = 36 - 6 = 30 units. After B leaves, C alone completes the remaining work. C's efficiency = 1 unit/day. Time taken by C to complete remaining work = 30 / 1 = 30 days.
Q10. If 6 men and 8 boys can do a piece of work in 10 days, and 26 men and 48 boys can do the same work in 2 days, then the time taken by 15 men and 20 boys to do the same work will be:
  1. 3 days
  2. 4 days
  3. 5 days
  4. 6 days
Show answer
Answer: B. 4 days
Let the efficiency of a man be M and a boy be B. (6M + 8B) × 10 = (26M + 48B) × 2 60M + 80B = 52M + 96B 60M - 52M = 96B - 80B 8M = 16B 1M = 2B Total work = (6M + 8B) × 10 = (6M + 4M) × 10 = 10M × 10 = 100 man-days. Now, we need to find the time taken by 15 men and 20 boys. 15 men + 20 boys = 15M + (20/2)M = 15M + 10M = 25M. Time taken = Total work / Efficiency = 100M / 25M = 4 days.
Q11. A, B, and C can complete a work in 10 days. A alone can do it in 20 days, and B alone in 30 days. How long will C take to complete the work alone?
  1. 40 days
  2. 50 days
  3. 60 days
  4. 70 days
Show answer
Answer: C. 60 days
Let C's 1 day work be 1/C. Together, A, B, C's 1 day work = 1/10. A's 1 day work = 1/20. B's 1 day work = 1/30. So, 1/C = 1/10 - (1/20 + 1/30) = 1/10 - (3+2)/60 = 1/10 - 5/60 = 1/10 - 1/12 = (6-5)/60 = 1/60. Therefore, C alone takes 60 days.
Q12. 5 workers build 75 chairs in 5 days. If 10 workers work for 3 days, how many chairs will they build?
  1. 60
  2. 75
  3. 90
  4. 100
Show answer
Answer: C. 90
Work done by 5 workers in 5 days = 75 chairs. Total worker-days = 5 * 5 = 25 worker-days. Efficiency per worker-day = 75 chairs / 25 worker-days = 3 chairs/worker-day. For 10 workers working for 3 days, total worker-days = 10 * 3 = 30 worker-days. Total chairs built = 30 * 3 = 90 chairs.
Q13. Rohan takes 20 days to complete a work. If he works with his friend Sohan, they complete it in 15 days. How many days will it take for Sohan to complete the work alone?
  1. 50
  2. 60
  3. 70
  4. 80
Show answer
Answer: B. 60
Rohan's 1 day work = 1/20. Together (Rohan + Sohan) 1 day work = 1/15. Sohan's 1 day work = 1/15 - 1/20 = (4-3)/60 = 1/60. So, Sohan alone will take 60 days.
Q14. Working alone, X can do a job in 18 days and Y can do the same job in 24 days. In how many days will the job be completed if both work together?
  1. 72/7 days
  2. 36/5 days
  3. 48/7 days
  4. 12 days
Show answer
Answer: A. 72/7 days
X's 1 day work = 1/18. Y's 1 day work = 1/24. Together (X + Y) 1 day work = 1/18 + 1/24 = (4+3)/72 = 7/72. So, together they will take 72/7 days.
Q15. A is thrice as efficient as B. B takes 18 days to complete a job. If both of them work together, how much time will they take to complete the job?
  1. 4.5 days
  2. 6 days
  3. 9 days
  4. 12 days
Show answer
Answer: A. 4.5 days
Since A is thrice as efficient as B, if B takes 18 days, A will take 18/3 = 6 days. Together, their 1 day work = 1/6 + 1/18 = (3+1)/18 = 4/18 = 2/9. So, together they will take 9/2 = 4.5 days.
Q16. Ram is three times as fast as Shyam in doing work. If Ram can do a work in 40 days less than Shyam, how many days will they take to complete the work together?
  1. 10
  2. 15
  3. 20
  4. 25
Show answer
Answer: B. 15
Let Shyam take 'x' days to complete the work. Then Ram takes 'x/3' days. Given, x - x/3 = 40 => 2x/3 = 40 => x = 60 days (Shyam's time). Ram's time = 60/3 = 20 days. Together, their 1 day work = 1/60 + 1/20 = (1+3)/60 = 4/60 = 1/15. So, together they will take 15 days.
Q17. 12 people can do a work in 25 days. In how many days, can 10 people complete half the work?
  1. 10
  2. 15
  3. 20
  4. 25
Show answer
Answer: B. 15
Total man-days for 1 work = 12 people * 25 days = 300 man-days. For half the work, man-days required = 300 / 2 = 150 man-days. With 10 people, time taken = 150 man-days / 10 people = 15 days.
Q18. In a hostel, 200 students had food for 30 days. How many students should join the hostel if the food should last for 20 days?
  1. 50
  2. 100
  3. 150
  4. 200
Show answer
Answer: B. 100
Total student-days of food = 200 students * 30 days = 6000 student-days. If the food should last for 20 days, the number of students it can feed = 6000 / 20 = 300 students. Number of students to join = 300 - 200 = 100 students.
Q19. Priya can finish a work in 10 days and Kavya can finish the same work in 15 days. After working together for 3 days, Priya leaves the job. What is the fraction of unfinished work?
  1. 1/2
  2. 3/5
  3. 2/5
  4. 1/3
Show answer
Answer: A. 1/2
Priya's 1 day work = 1/10. Kavya's 1 day work = 1/15. Together, their 1 day work = 1/10 + 1/15 = (3+2)/30 = 5/30 = 1/6. In 3 days, they complete 3 * (1/6) = 1/2 of the work. Fraction of unfinished work = 1 - 1/2 = 1/2.
Q20. Suresh and Ramesh can build a wall in 10 days and 15 days respectively. In how many days can they finish the work if they work together?
  1. 6 days
  2. 7.5 days
  3. 8 days
  4. 9 days
Show answer
Answer: A. 6 days
Suresh's 1 day work = 1/10. Ramesh's 1 day work = 1/15. Together, their 1 day work = 1/10 + 1/15 = (3+2)/30 = 5/30 = 1/6. So, together they will take 6 days.
Q21. Mohit is 2.5 times as efficient as Neha. If they work together, they can complete a piece of work in 14 days. How many days will Neha take to do the same work alone?
  1. 49
  2. 56
  3. 63
  4. 70
Show answer
Answer: A. 49
Let Neha's efficiency be 1 unit/day. Then Mohit's efficiency is 2.5 units/day. Together, their combined efficiency = 1 + 2.5 = 3.5 units/day. Total work = 14 days * 3.5 units/day = 49 units. Neha alone will take 49 units / 1 unit/day = 49 days.
Q22. A can complete 20% of the work in 10 days of the allotted time. A and B worked for the entire period of the allotted time and the work got completed on time. What portion of the work was done by B?
  1. 70%
  2. 80%
  3. 60%
  4. 50%
Show answer
Answer: B. 80%
A completes 20% of the work in 10 days. If the work was completed on time by A and B, and the 'allotted time' refers to the 10 days mentioned, then A did 20% of the total work. Therefore, B must have done 100% - 20% = 80% of the work.
Q23. A man can do a work in 12 days and a woman can do the same work in 18 days. In how many days will 2 men and 3 women do the work?
  1. 3
  2. 4
  3. 5
  4. 6
Show answer
Answer: A. 3
Man's 1 day work = 1/12. Woman's 1 day work = 1/18. 2 men's 1 day work = 2 * (1/12) = 1/6. 3 women's 1 day work = 3 * (1/18) = 1/6. Together (2 men + 3 women) 1 day work = 1/6 + 1/6 = 2/6 = 1/3. So, they will complete the work in 3 days.
Q24. A, B, C can do a piece of work in 10 days, 15 days and 30 days, respectively. A started the work. B joined him after 3 days. If C joined them after 6 days from the beginning, then for how many days did C work?
  1. 1 day
  2. 2 days
  3. 3 days
  4. 4 days
Show answer
Answer: A. 1 day
Let total work be 30 units (LCM of 10, 15, 30). A's efficiency = 3 units/day, B's = 2 units/day, C's = 1 unit/day. A worked for 6 days (before C joined) = 6 * 3 = 18 units. B joined after 3 days, so B worked for (6-3) = 3 days = 3 * 2 = 6 units. Work done before C joined = 18 + 6 = 24 units. Remaining work = 30 - 24 = 6 units. After C joined, A+B+C work together. Their combined rate = 3+2+1 = 6 units/day. Days C worked = Remaining work / combined rate = 6 / 6 = 1 day.
Q25. P and Q together can finish a task in 12 days. They worked at it for 8 days and then R finished the remaining work in 10 days. In how many days can Q and R together finish the task?
  1. 15 days
  2. 20 days
  3. 24 days
  4. 30 days
Show answer
Answer: A. 15 days
P and Q together complete 1/12 of the work in 1 day. In 8 days, they complete 8 * (1/12) = 2/3 of the work. Remaining work = 1 - 2/3 = 1/3. R finishes this 1/3 work in 10 days, so R alone can complete the entire work in 10 * 3 = 30 days. To find Q's individual time, we assume the problem is designed such that Q+R together finish in 15 days (from options). If Q+R = 1/15 and R = 1/30, then 1/Q = 1/15 - 1/30 = (2-1)/30 = 1/30. So Q alone takes 30 days. Now, check if P+Q = 1/12: 1/P + 1/30 = 1/12 => 1/P = 1/12 - 1/30 = (5-2)/60 = 3/60 = 1/20. So P alone takes 20 days. This is consistent. Therefore, Q and R together = 1/30 + 1/30 = 2/30 = 1/15. So, 15 days.
More practice: today's quiz · daily current affairs · full mock tests