Time and Work Questions

Multiple choice
  1. 10 days

  2. 15 days

  3. 20 days

  4. 25 days

  5. 22 days

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

Let 1 man's 1 day work = m, 1 woman's 1 day work = w. 5m × 15 = 1 (total work). Work done in first 5 days = 5m × 5 = 1/3. Remaining work = 2/3. In next 5 days: (5m + 10w) × 5 = 2/3, so 5m + 10w = 2/15. Since 5m = 1/15, we get 1/15 + 10w = 2/15, so 10w = 1/15. If 10 women do the work alone: Time = 1/(10w) = 1/(1/15) = 15 days. Option B is correct.

Multiple choice
  1. 38 days

  2. 30 days

  3. 23 days

  4. 26 days

  5. 19 days

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

Let B's efficiency = 1 unit/day. Then A's efficiency = 1.3 units/day (30% more). Let total work = W. B works for 12 days: work done = 12 units. Remaining work = W - 12. A completes this in 20 days: 1.3 × 20 = 26 units = W - 12. Therefore W = 38 units. B's rate = 1 unit/day, so B alone takes 38 days for full work. For half the work: 38/2 = 19 days.

Multiple choice
  1. 8

  2. 7

  3. 12

  4. 14

  5. can't be determined

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

Let 1 man's work = 1 unit/day. Then 1 woman = 2 units, 1 boy = 0.5 units. Combined work per day = 3(1) + 4(2) + 6(0.5) = 3 + 8 + 3 = 14 units. Total work = 14 × 7 = 98 units. For 7 women: work per day = 7 × 2 = 14 units. So 7 women complete 98 units in 98/7 = 7 days.

Multiple choice
  1. 30 days

  2. 40 days

  3. 25 days

  4. 24 days

  5. 20 days

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

Let Shyam take x days. Ram takes (x-10) days. Combined rate: 1/x + 1/(x-10) = 1/12. Solving: (2x-10)/(x²-10x) = 1/12, so 12(2x-10) = x²-10x, giving x²-34x+120=0. (x-30)(x-4)=0, so x=30 (rejecting x=4 as x-10 would be negative). Shyam takes 30 days alone. Option A is correct.

Multiple choice
  1. 10

  2. 5

  3. 20

  4. 30

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

Total work = 20 men × 80 days = 1600 man-days. Work completed in 60 days = 20 × 60 = 1200 man-days. Remaining work = 400 man-days. After 10-day stoppage, only 10 days remain. Men needed = 400/10 = 40 men. Additional men required = 40 - 20 = 20 men. Option A (10) would give only 30 men total, insufficient to complete in 10 days.

Multiple choice
  1. 8 days

  2. 6 days

  3. 5 days

  4. 3 days

  5. 2 days

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

Radha's rate: 1/16 work/day; Meera's rate: 1/10 work/day. Let d = total days. Radha works d days, Meera works (d − 3) days (leaves 3 days early). Total work: d/16 + (d−3)/10 = 1. Solving: 10d + 16(d−3) = 160 → 26d = 208 → d = 8 days.

Multiple choice
  1. 30

  2. 32

  3. 36

  4. 38

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

Work rates: Man = 1/40 per day, Woman = 1/60 per day, Boy = 1/120 per day. In 2 days: 2 men complete 2×(2/40) = 1/10, 8 women complete 2×(8/60) = 8/15. Total from men and women = 1/10 + 8/15 = 35/150. Remaining work = 1 - 35/150 = 115/150. Each boy does 2/120 = 1/60 in 2 days. Boys needed = (115/150) / (1/60) = 46. So we need 46 boys. Wait, let me verify: 46/60 = 23/30 = 115/150. Yes, 46 boys. But 46 isn't an option. Let me reconsider: 2 men in 2 days = 4/40 = 1/10 = 15/150. 8 women in 2 days = 16/60 = 4/15 = 40/150. Total = 55/150 done. Remaining = 95/150 = 19/30. Each boy in 2 days = 2/120 = 1/60. Boys needed = (19/30)/(1/60) = 38. Option D is correct.

Multiple choice
  1. 32 days/दिन

  2. 40 days/दिन

  3. 48 days/दिन

  4. 30 days/दिन

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

A+B rate = 1/16 per day, B+C rate = 1/24 per day. A works 4 days, B works 7 days, C works 23 days. Total work = (A+B)×4 + (B+C)×23 - B×(4+7-16) = W. Through algebraic manipulation, C's rate = 1/32 work per day, so C takes 32 days alone.

Multiple choice
  1. 44

  2. 33

  3. 66

  4. 55

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

12 men = 24 boys, so 1 man = 2 boys. 15 men + 6 boys = 15(2) + 6 = 36 boys. If 24 boys take 66 days, 36 boys take 24×66/36 = 44 days. 33, 55, and 66 are incorrect as they don't properly account for the combined workforce efficiency.