Time, Speed and Distance Questions

Multiple choice
  1. 9km

  2. 24km

  3. 10km

  4. None of these

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

Downstream distance = 15km in 12 minutes = 75kmph. Downstream speed = rowing speed + current, so current = 75 - 56 = 19kmph. Upstream speed = 56 - 19 = 37kmph. In 20 minutes (1/3 hour), upstream distance = 37 × (1/3) = 12.33km, which is not among options A-C. Hence D is correct.

Multiple choice
  1. 10 sec

  2. 15 sec

  3. 18 sec

  4. 20 sec

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

The train's length must cover the entire distance relative to the man. Relative speed = (36-9) kmph = 27 kmph = 27 × 5/18 = 7.5 m/s. Time = Distance/Relative Speed = 150m/7.5 m/s = 20 seconds. The man is moving in the same direction, so we subtract speeds.

Multiple choice
  1. 20 km

  2. 24 km

  3. 16 km

  4. 32 km

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

Let distance by train = d km. Time by train = d/50 hours. Time running back = d/8 hours. Total time = 2 hours 54 min = 2.9 hours = 29/10 hours. Therefore: d/50 + d/8 = 29/10. Multiplying by 200: 4d + 25d = 580, so 29d = 580, hence d = 20 km. Verify: 20/50 + 20/8 = 0.4 + 2.5 = 2.9 hours = 2 hours 54 minutes.

Multiple choice
  1. 144 kmph 144 किमी./घंटा

  2. 72 kmph 72 किमी./घंटा

  3. 40 kmph 40 किमी./घंटा

  4. 120 kmph 120 किमी./घंटा

  5. None of these इनमें से कोई नहीं

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

Distance = 384 km. Return time = 5h 36min = 5.6 hours. Return speed = Distance/Time = 384/5.6 = 68.57 km/h. The options (144, 72, 40, 120 km/h) don't include the correct answer. Option E (None of these) is correct.

Multiple choice
  1. 25

  2. 12

  3. 12.5

  4. 18

  5. 15

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

Let distance = d km and correct time = t hours. At 15 km/h: d/15 = t - 5/60 (5 minutes early). At 10 km/h: d/10 = t + 20/60 (20 minutes late). Subtracting: d/10 - d/15 = 25/60 = 5/12 hours. d/30 = 5/12. d = 150/12 = 12.5 km. The distance between house and office is 12.5 km.

Multiple choice
  1. 10 km. 10 किमी.

  2. 8 km. 8 किमी.

  3. 7 km. 7 किमी.

  4. 6 km. 6 किमी.

  5. Cannot be determined निर्धारित नहीं किया जा सकता है।

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

Let stream speed be s km/hr. Distance = d. Total time = d/(4-s) + d/(4+s) = 6. Solving gives d = 12(4-s^2) km. Since s is unknown but must be less than 4 (otherwise boat cannot go upstream), there are multiple possible (s,d) pairs. Without additional information about the stream, distance cannot be uniquely determined.

Multiple choice
  1. 360

  2. 380

  3. 400

  4. 480

  5. None of these इनमे से कोई नही|

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

Let original speed be v km/h. Original time = 1600/v hours. New speed = (v + 80) km/h. New time = 1600/(v + 80) hours. Time saved = 40 minutes = 2/3 hour. So 1600/v - 1600/(v + 80) = 2/3. Solving: 1600(v + 80 - v)/[v(v + 80)] = 2/3, which gives 128000/[v(v + 80)] = 2/3, or v(v + 80) = 192000. Solving v^2 + 80v - 192000 = 0 gives v = 400 or v = -480. Since speed is positive, v = 400 km/h.

Multiple choice
  1. 25 kmph

  2. 50 kmph

  3. 75 kmph

  4. 150 kmph

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

Average speed = total distance / total time. Total distance = 24 km. Total time = 6/25 + 6/50 + 6/75 + 6/150 = 6(1/25+1/50+1/75+1/150) = 6(6/150+3/150+2/150+1/150) = 6(12/150) = 72/150 hr. Speed = 24/(72/150) = 50 km/h. This is the harmonic mean of 25, 50, 75, 150 for equal distances. Option C (75) is a distractor - the arithmetic mean of extremes.

Multiple choice
  1. 48

  2. 36

  3. 40

  4. 32

  5. None of these इनमे से कोई नही|

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

Let speeds be 5x and 4x km/hr. Relative speed = 5x - 4x = x km/hr. Distance to catch up = 8 km. Time = 8/x hours. Distance fast train travels = speed × time = 5x × (8/x) = 40 km.

Multiple choice
  1. 60 km./hr. 60 किमी / घंटा

  2. 50 km./hr. 50 किमी / घंटा

  3. 40 km./hr. 40 किमी / घंटा

  4. 30 km./hr. 30 किमी / घंटा

  5. 20 km./hr. 20 किमी / घंटा

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

Distance = 60 × 15 = 900 km. New speed = 900/9 = 100 km/hr. Increase needed = 100 - 60 = 40 km/hr. Option A (60) incorrectly doubles the original speed instead of finding the difference.

Multiple choice
  1. 2.1 kmph 2.1 किमी/घंटा

  2. 1.5 kmph 1.5 किमी/घंटा

  3. 4.4 kmph 4.4 किमी/घंटा

  4. 2.4 kmph 2.4 किमी/घंटा

  5. None of these इनमें से कोई नहीं

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

Let boat speed = 12 kmph (still water), stream speed = s. Downstream speed = 12+s, upstream = 12-s. Distance same, so (12+s)×12 = (12-s)×18. Solving: 144 + 12s = 216 - 18s, so 30s = 72, s = 2.4 kmph. Verification: Downstream speed = 14.4 kmph, distance = 172.8 km. Upstream speed = 9.6 kmph, time = 172.8/9.6 = 18 hours. Answer D is correct.

Multiple choice
  1. 4.28

  2. 5.15

  3. 2.96

  4. 3.21

  5. 3.67

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

Total distance = 20+15+10 = 45 km. Time for each leg: 20/5=4 hrs, 15/3=5 hrs, 10/2=5 hrs. Total time = 14 hrs. Average speed = Total distance/Total time = 45/14 ≈ 3.21 km/h. This matches option D.

Multiple choice
  1. 115 Km 115 किमी

  2. 96 Km 96 किमी

  3. 108 Km 108 किमी

  4. 72 Km 72 किमी

  5. None of these इनमे से कोई नहीं

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

Speed in still water = 15 kmph, river speed = 3 kmph. Downstream speed = 15 + 3 = 18 kmph. Upstream speed = 15 - 3 = 12 kmph. Let distance be d. Time downstream = d/18, time upstream = d/12. Given: d/12 - d/18 = 3 hours. Solving: d(1/12 - 1/18) = 3, d(1/36) = 3, d = 108 km.