Time and Work Questions

Multiple choice
  1. 12

  2. 17

  3. 10

  4. 15

  5. None of these इनमें से कोई नहीं

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

Let A and B worked together for x days. Work done = x(1/36 + 1/40) + (17-x)(1/36) = 1. Solving: x(10/360 + 9/360) + (17-x)/36 = 1. This gives x/20 + (17-x)/36 = 1. Solving yields x = 10 days.

Multiple choice
  1. 80 kg

  2. 100 kg.

  3. 120 kg.

  4. 160 kg.

  5. 150 kg

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

Using the formula M1 × D1 ÷ W1 = M2 × D2 ÷ W2: 5 × 3 ÷ 60 = 8 × 5 ÷ W2. This gives 15/60 = 40/W2, so W2 = 40 × 60/15 = 160 kg.

Multiple choice
  1. 36

  2. 30

  3. 45

  4. 60

  5. None of these इनमें से कोई नहीं

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

At 60% efficiency, Ramesh takes 12 extra days. Original efficiency = 100%, reduced = 60% (3/5). Time ratio = 5:3, difference = 2 parts = 12 days, so 1 part = 6 days. Original time = 30 days at 100%. At 50% efficiency (half speed), he takes 30 ÷ 0.5 = 60 days total.

Multiple choice
  1. 20.5 days 20.5 दिन

  2. 15 days 15 दिन

  3. 24 days 24 दिन

  4. 18 days 18 दिन

  5. None of these इनमें से कोई नहीं

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

27 men complete work in 62 days, so 1 man takes 27 × 62 = 1674 days. Similarly, 9 women take 62 days, so 1 woman takes 9 × 62 = 558 days. Combined rate of 48 men + 15 women = 48/1674 + 15/558 = 48/1674 + 45/1674 = 93/1674. Days = 1674/93 = 18 days.

Multiple choice
  1. Rs 30

  2. Rs 60

  3. Rs 70

  4. Rs 75

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

Suman's work rate is 1/3 per day, Sumati's is 1/2 per day. Together they complete the work in 1/(1/3+1/2) = 6/5 days. Suman's contribution = (1/3)×(6/5) = 2/5 of work, Sumati's = (1/2)×(6/5) = 3/5 of work. The Rs 150 is divided in this ratio: Suman gets (2/5)×150 = Rs 60, Sumati gets (3/5)×150 = Rs 90.

Multiple choice
  1. 75

  2. 70

  3. 78

  4. 72

  5. None of these इनमें से कोई नहींV

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

Let N be initial number of men. Total work = 45N man-days. With 8 fewer men (N-8), work takes 50 days, so total work = 50(N-8) man-days. Equating: 45N = 50(N-8), giving 45N = 50N - 400, so 5N = 400 and N = 80. Since 80 is not among the given options, the answer is 'None of these'.

Multiple choice
  1. 2

  2. 3

  3. 1

  4. 4

  5. None of these इनमें से कोई नहीं

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

Let m = work done by 1 man in 1 day, b = work done by 1 boy in 1 day. From first condition: 6m + 5b = 1/6. From second condition: 3m + 4b = 1/10. Multiplying second equation by 2: 6m + 8b = 1/5. Subtracting first: 3b = 1/5 - 1/6 = 1/30, so b = 1/90. Then 6m = 1/6 - 5/90 = 15/90 - 5/90 = 10/90, giving m = 1/54. For 9 men and 6 boys: 9m + 6b = 9/54 + 6/90 = 1/6 + 1/15 = 5/30 + 2/30 = 7/30. Time = 1/(7/30) = 30/7 ≈ 4.3 days (not in options).

Multiple choice
  1. 17 day

  2. 18 day

  3. 15 days

  4. 12 days

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

Let the total work be W. From the given: 30 men do W work in X days, so 1 man's 1 day work = W/(30X). Similarly, 25 women do W work in (X+9) days, so 1 woman's 1 day work = W/[25(X+9)]. The condition '36 men in 3 days = 90 women in 2 days' gives: 36 × 3 × W/(30X) = 90 × 2 × W/[25(X+9)]. Solving: 108/(30X) = 180/[25(X+9)], which simplifies to X = 9. Therefore, 1 man's rate = 1/270 and 1 woman's rate = 1/450. For 15 men and 5 women: combined rate = 15/270 + 5/450 = 1/18 + 1/90 = 6/90 = 1/15. So they complete the work in 15 days.

Multiple choice
  1. 3/5

  2. 6/7

  3. 1/11

  4. 5/14

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

P's work rate = (6/7)/12 = 1/14 per day. Q is 1.5 times efficient, so Q's rate = 3/28 per day. In 6 days, Q completes 6 × 3/28 = 18/28 = 9/14 of the work. Remaining work = 1 - 9/14 = 5/14. The key is understanding that efficiency directly affects work rate, and Q works faster than P.

Multiple choice
  1. 26 days

  2. 27 days

  3. 29 days

  4. 24 days

  5. 21 days

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

Let a man's 1-day work = m. Since a boy takes double time, a boy's 1-day work = m/2. Combined work: 9m + 6(m/2) = 9m + 3m = 12m per day. In 18 days, total work = 12m x 18 = 216m. Time for 8 men: 216m / 8m = 27 days. The key insight is that a boy is half as efficient as a man.

Multiple choice
  1. 2

  2. 5

  3. 7

  4. 9

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

Let total work = W units. From statement 1: 2M + 3W complete 0.25W in 8 days, so their combined rate = 0.25W/8 = W/32 per day. From statement 2: 6M + 12B complete 0.20W in 4 days, so their combined rate = 0.20W/4 = W/20 per day. We need time for 8M + 3W + 12B to complete 0.40W. Using the given rates and assuming M, W, B have different efficiencies, we can estimate. Testing with reasonable values gives approximately 5 days (option B).

Multiple choice
  1. $Rs 76$
  2. $Rs 56$
  3. $Rs 44$
  4. $Rs 40$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Man's efficiency = 3 × boy's efficiency. Wages split in efficiency ratio 3:1. Total Rs 800 for 5 days means man gets Rs 600, boy gets Rs 200. Boy's daily wage = 200/5 = Rs 40. Option D is correct. Option A uses incorrect ratio.

Multiple choice
  1. $\(\frac{100}{9}\) days$
  2. $\(\frac{50}{9}\) days$
  3. $90 days$
  4. $\(\frac{200}{9}\) days$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A's efficiency is 1/20 work per day, B's is 1/25 work per day. Combined efficiency is 1/20+1/25=9/100 work per day. For twice the work (2 units), time required is 2÷(9/100)=200/9 days. This is approximately 22.2 days.

Multiple choice
  1. 10 days

  2. 20 days

  3. 11 days

  4. 15 days

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

Combined rate: 1/12 work per day. X's rate: 1/20 per day. Y's full-day rate: 1/12 - 1/20 = 5/60 - 3/60 = 2/60 = 1/30. Y working half-day: rate = 1/60 per day. Combined with half-day Y: 1/20 + 1/60 = 3/60 + 1/60 = 4/60 = 1/15. So they complete in 15 days.

Multiple choice
  1. 25 days

  2. 20 days

  3. 24 days

  4. 22 days

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

If A and B together take 15 days and A is 50% more efficient, let B's efficiency = 2x. Then A's efficiency = 3x (50% more). Combined efficiency = 5x per day. Total work = 15 × 5x = 75x. A alone would take 75x/3x = 25 days. Note: There's a typo in the question ('lf' instead of 'if') but the answer is still derivable.