Time and Work Questions

Multiple choice
  1. 48

  2. 60

  3. 54

  4. 72

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

P is twice as good as Q means P's efficiency = 2 × Q's efficiency. Together they finish in 36 days. Combined efficiency = P + Q = 2Q + Q = 3Q. If 3Q takes 36 days, Q alone would take 36 × 3 = 108 days. P alone (who is twice as good) would take 108/2 = 54 days.

Multiple choice
  1. Rs. 420

  2. Rs. 480

  3. Rs. 560

  4. Rs. 500

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

Let work done by 1 man in 1 day = m and 1 boy = b. From the given: 10(5m + 7b) = 12(4m + 7b) = W. Solving gives m = 0.1W and b = W/84. Total work W = 84 units. Daily wage for 1 man = Rs.140 corresponds to 0.1W work, so per unit wage = Rs.140/8.4. Daily wages of 3 men and 4 boys = 3m + 4b = 0.3W + 4W/84 = (0.3 + 4/84)W = Rs.500. Option D is correct.

Multiple choice
  1. 1200

  2. 1500

  3. 1600

  4. 1800

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

X's rate = 1/18, Y's rate = 1/24. Combined rate of X+Y+Z = 1/8. Z's rate = 1/8 - 1/18 - 1/24 = (9-4-3)/72 = 2/72 = 1/36. Z's share = (1/36)×8×5400 = 1200.

Multiple choice
  1. 5

  2. 6

  3. 4

  4. 3

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

A's work rate is 1/15 per day, B's rate is 1/30 per day. Together they do 1/15 + 1/30 = 3/30 = 1/10 of the work per day. So they complete the full work in 10 days. For 50% of the work, they need 10 × 0.5 = 5 days.

Multiple choice
  1. 6.4

  2. 7.2

  3. 5.8

  4. 7.1

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

P+Q = 1/8, Q+R = 1/16, R+P = 1/8 work per day. Adding all: 2(P+Q+R) = 1/8 + 1/16 + 1/8 = 5/16, so P+Q+R = 5/32 work per day. Time = 32/5 = 6.4 days. When all three work together, they complete the work faster. Options B, C, and D are incorrect estimates.

Multiple choice
  1. 12

  2. 24

  3. 36

  4. 48

  5. 60

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

Let P, Pu, R be one-day work of Pinky, Puja, Riya. Given: P + Pu = 1/24, Pu + R = 1/32. After Pinky works 10 days, Puja works 14 days, and Riya finishes in 26 days: 10P + 14Pu + 26R = 1. Substituting P = 1/24 - Pu and solving: 4Pu + 26R = 7/12. Using Pu = 1/32 - R gives 26R - 4R = 7/12 - 1/8, so 22R = 11/24, thus R = 1/48. Therefore Riya alone takes 48 days.

Multiple choice
  1. 20

  2. 15

  3. 30

  4. 10

  5. 12

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

Boy's efficiency = 1 unit. Man = 2 × boy = 2 units. Woman = (2/3) × man = 4/3 units. Total work = 8 × 20 = 160 boy-days = 160 units. Combined efficiency of 4 men + 6 women = 4(2) + 6(4/3) = 8 + 8 = 16 units/day. Days = 160/16 = 10 days.

Multiple choice
  1. 12

  2. 10

  3. 8

  4. 16

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

Anju completes 3/4 of job in 18 days, so full job takes 18 × 4/3 = 24 days. Prachi is twice as efficient, so Prachi takes 24/2 = 12 days. Efficiency is inversely proportional to time taken.

Multiple choice
  1. 10 hours/ घंटे

  2. 14 hours/ घंटे

  3. 8 hours/ घंटे

  4. 12 hours/ घंटे

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

Work = workers × days × hours/day. Original work = 24 × 18 × 7 = 3024 work-hours. New work needed = 2 × 3024 = 6048 work-hours. Required hours/day = 6048 ÷ (36 × 14) = 6048 ÷ 504 = 12 hours. This uses the work formula and the inverse relationship between workers/hours and the direct relationship with amount of work.

Multiple choice
  1. 30

  2. 40

  3. 50

  4. 60

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

A and B together do 1/30 of work per day. In 16 days, A does 16/A of work. Remaining work = 1 - 16/A. B completes this in 44 days at rate 1/B per day, so (1 - 16/A) = 44/B. Also 1/A + 1/B = 1/30. From the work equation: B(1 - 16/A) = 44, so B - 16B/A = 44. Since 1/A = 1/30 - 1/B, we get B - 16B(1/30 - 1/B) = 44, which gives B - 16B/30 + 16 = 44, so B(1 - 16/30) = 28, B(14/30) = 28, B = 28 × 30/14 = 60 days.

Multiple choice
  1. 15

  2. 12

  3. 10

  4. 18

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

Efficiency ratio A:B:C = 5:4:3. Total efficiency working together = 5+4+3 = 12 units/day. Work completed in 25 days, so total work = 12 × 25 = 300 units. B and C's combined efficiency = 4+3 = 7 units/day. 35% of work = 0.35 × 300 = 105 units. Time for B and C to complete 105 units = 105/7 = 15 days.

Multiple choice
  1. 20

  2. 30

  3. 25

  4. 18

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

A and B together complete work in 12 days. Their profit shares (1443:962 = 3:2) reflect their work rates. If A's work rate is 3x and B's is 2x, then (3x + 2x) × 12 = 1 job, so 60x = 1. A alone takes 1/(3x) = 1/(3/60) = 20 days. Profit sharing is directly proportional to work contribution in partnerships.

Multiple choice
  1. 18

  2. 21

  3. 19

  4. 21.5

  5. 22

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

If Amit does 3/4 of work in 5/6 of Bhanu's time, Amit's rate : Bhanu's rate = (3/4)/(5/6) = 9:10. Together in 10 days: (9+10)/10k = 1/10, so k = 1. Bhanu alone: 10/1 = 10 days for full work. But wait - let me recalculate. Amit's efficiency = (3/4 work)/(5/6 time) = 9/10 of Bhanu. So if Bhanu takes x days, Amit takes x/(9/10) = 10x/9 days. Together: 1/x + 9/(10x) = 1/10. 19/(10x) = 1/10, x = 19. Bhanu takes 19 days.

Multiple choice
  1. Quantity II < Quantity I

  2. Quantity II > Quantity I

  3. Quantity II ≤ Quantity I

  4. Quantity II ≥ Quantity I

  5. Quantity II = Quantity I or relation cannot be established

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

Quantity I: 1/A + 1/B = 1/8, 1/B + 1/C = 1/12, 1/C + 1/A = 1/8. Adding first and third: 2/A + 1/B = 1/4. Subtract second: 2/A - 1/C = 1/6. But 1/A = 1/8 - 1/B, so A alone = 9.6 days. Quantity II: A+B work = 6/18 = 1/3. Remaining = 2/3 done by B in 24 days, so 1/B = (2/3)/24 = 1/36, B = 36 days. Then 1/A = 1/18 - 1/36, A = 36 days. Quantity II (36) > Quantity I (9.6).

Multiple choice
  1. 5

  2. 6

  3. 7

  4. 8

  5. 9

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

One man completes 1/11 of the work per day. On day n, n men work, completing n/11 of the work. After day 8, no new men are added, so 9 men work from day 9 onwards. Sum of work from day 1 to day 8 is the sum of 1/11 to 8/11 = (1+2+...+8)/11 = 36/11. From day 9 onwards, 9 men work, so they complete 9/11 per day. To complete 4 times (44/11) of the work: 36/11 + 9/11 = 45/11, which exceeds 44/11, so the work completes on day 9.