Time and Work Questions

Multiple choice
  1. 2.4 days 2.4 दिन

  2. 1.6 days 1.6 दिन

  3. 1.9 days 1.9 दिन

  4. 9 days 9 दिन

  5. None of these इनमें से कोई नहीं

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let C's efficiency = 1 unit. Then A's efficiency = 3 units (A is thrice as efficient as C). B's efficiency = 2 units (C is half as efficient as B, so B is twice C). Time taken is inversely proportional to efficiency. If C takes t days, A takes t/3 days. Difference: t - t/3 = 2t/3 = 8 days, so t = 12 days. Therefore A takes 12/3 = 4 days alone. B takes 12/2 = 6 days alone. Together their rate = 1/4 + 1/6 = 5/12 work per day. Time together = 1 / (5/12) = 12/5 = 2.4 days. Option B (1.6) and C (1.9) are calculation errors, D (9) ignores efficiency.

Multiple choice
  1. 12 days 12 दिन

  2. 15 days 15 दिन

  3. 18 days 18 दिन

  4. 10 days 10 दिन

  5. 16 days 16 दिन

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let individual rates be A, B, C. Given: A+B+C=1/6, A+B=1/10, B+C=1/12. Subtracting: C=(A+B+C)-(A+B)=1/6-1/10=1/15. So C alone takes 15 days for full work. At 75% efficiency, C's rate becomes 0.75×(1/15)=1/20. For 60% of work: Time=0.6÷(1/20)=12 days. The calculations verify option A.

Multiple choice
  1. 42

  2. 45

  3. 35

  4. 24

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Total work = 48 × 120 = 5760 person-days. Work done in x days by 48 persons = 48x. Remaining work done by 40 persons (8 left) in (137 - x) days = 40(137 - x). Setting up: 48x + 40(137 - x) = 5760, which simplifies to 8x = 280, giving x = 35. Option A (42) incorrectly assumes no productivity change, while Option D (24) would require 48×24 + 40×113 < 5760.

Multiple choice
  1. 12 days

  2. 24 days

  3. 36 days

  4. 16 days

  5. None of these

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

Pramod does 66.6% = 2/3 of work. Remaining = 1/3. Shreya does 12.5% = 1/8 of remaining = 1/8 × 1/3 = 1/24 of total work. Remaining for Ankit = 1/3 - 1/24 = 7/24. Ankit completes 7/24 in 7 days, so total work takes 24 days. Option B correct.

Multiple choice
  1. 20 days

  2. 18 days

  3. 17 days

  4. 12 days

  5. None of these

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Akshay's rate: (1/3)/15 = 1/45 per day. Aamir's rate: 0.75/18 = 1/24 per day. Ajay's rate: 1/36 per day. Aamir + Ajay combined: 1/24 + 1/36 = 5/72 per day. In 8 days they complete: 8 × 5/72 = 5/9 of work. Remaining: 1 - 5/9 = 4/9. Akshay's time: (4/9) / (1/45) = 20 days.

Multiple choice
  1. 8 days

  2. 12 days

  3. 10 days

  4. 6 days

  5. 9 days

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Take total work as LCM(24,30,40) = 120 units. Harry does 5 units/day, Peter does 4 units/day, Vinod does 3 units/day. Harry and Vinod together do 8 units/day. They worked for 4 days initially and 6 days finally, totaling 10 days. Work done by H+V = 10 × 8 = 80 units. Remaining work = 120 - 80 = 40 units, done by Peter at 4 units/day, taking 40/4 = 10 days.

Multiple choice
  1. 42

  2. 48

  3. 53

  4. 43

  5. None of these

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

Shridhar's 1-day work = 1/75, so Shravan's 1-day work = 1/25 - 1/75 = 2/75. With Pawan, 1-day work = 1/8, so Pawan's 1-day work = 1/8 - 1/25 = 17/200. Total 1-day work of all three = 1/75 + 2/75 + 17/200 = 3/75 + 17/200 = 1/25 + 17/200 = 25/200 = 1/8. Shravan's share = (2/75)/(1/8) × 225 = 16/75 × 225 = 16 × 3 = 48.

Multiple choice
  1. 21690

  2. 21600

  3. 22000

  4. 34000

  5. None of these

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

Let Banner's rate be B/day. Peter's rate = 54000/10 = 5400/day. Total work: 3 days together (5400+B), 3 days Banner alone (B), 3 days Peter alone (5400) = 54000. Solving: 3(5400+B) + 3B + 3(5400) = 54000 → 32400 + 6B = 54000 → B = 3600/day. Banner works 6 days total (3 with Peter + 3 alone), earning 6 × 3600 = Rs. 21600.

Multiple choice
  1. I only

  2. II only

  3. I & II

  4. I, II & III

  5. None of the above

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Given Kapil+Chandan complete work in 6 days earning Rs.1350, we need to find how Rs.1200 would be split if Sunil joins. Statement I gives Kapil:Sunil days ratio (5:9), Statement II gives Kapil:Chandan efficiency (3:2). With I+II, we can determine individual efficiencies and calculate the new ratio. Statement III (Sunil least efficient) doesn't add needed quantitative data. Thus only I and II together are sufficient.

Multiple choice
  1. 15th day

  2. 16th day

  3. 17th day

  4. 18th day

  5. None of these

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Maddy and Mohan together do 2/29 of work per day. After 16 days, Maddy worked 13 days (3 rests) and Mohan worked 13 days (3 rests). Total 26 days of work = 26 × 2/29 = 52/29 ≈ 1.79 times the work. This suggests completion on day 17 when Maddy works again.

Multiple choice
  1. 140

  2. 120

  3. 210

  4. 190

  5. None of these

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let W be the initial number of men and D be the total work. Each day, 20 men drop out, so day n has W - 20(n-1) men. Work done each day: (W-20) + (W-40) + ... + (W-120) = 7W - 420 = 5W (since 5W men would complete it in 5 days). Solving: 7W - 420 = 5W gives W = 210. The arithmetic progression of workers declining by 20 each day is the key insight.

Multiple choice
  1. 42 days

  2. 40 days

  3. 35 days

  4. 38 days

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let total work be LCM(14,21)=42 units. P+Q do 3 units/day and Q+R do 2 units/day. Since P is twice as efficient as R, let R=1 unit/day, then P=2 units/day. From Q+R=2, we get Q=1 unit/day. Q alone takes 42/1=42 days.

Multiple choice
  1. 35 days

  2. 33 days

  3. 34 days

  4. 40 days

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

A's rate = 1/60 work/day. B is 25% more efficient, so B's rate = 1.25 × 1/60 = 1/48 work/day. C is 20% more efficient than B, so C's rate = 1.2 × 1/48 = 1/40 work/day. B does 37.5% = 3/8 of work at rate 1/48, taking (3/8)/(1/48) = 18 days. Remaining work = 5/8 at rate (1/60 + 1/40) = 1/24, taking (5/8)/(1/24) = 15 days. Total = 18 + 15 = 33 days.

Multiple choice
  1. 32 days

  2. 26 days

  3. 30 days

  4. 20 days

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Work = 60 × 20 + 80 × 60 = 4800 man-days. Without additional men: 60 × 80 would complete 4800 man-days, but we need to find when 60 men complete 4800 - 1600 = 3200 man-days. Time = 3200/60 = 53.33 days. Total would be 20 + 53.33 ≈ 73.33 days. Extra days = 73.33 - 80 = 6.67, but we need 80 - 60 = 20 more days total. Actually: 60 men in 100 days complete 4800. So extra = 100 - 80 = 20 days.

Multiple choice
  1. 20 days

  2. 18 days

  3. 14 days

  4. 16 days

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

6 boys complete work in 24 days, so 1 boy takes 144 days. 12 girls complete work in 24 days, so 1 girl takes 288 days. Work rate of 1 boy = 1/144 per day, 1 girl = 1/288 per day. Combined rate of 5 boys + 8 girls = 5/144 + 8/288 = 10/288 + 8/288 = 18/288 = 1/16 per day. Therefore, they complete the work in 16 days. Option A (20 days) would require a slower combined rate. Option B (18 days) and C (14 days) don't match the calculated rate.