Time, Speed and Distance Questions

Multiple choice
  1. 7.5 km./किमी.

  2. 6 km./किमी.

  3. 5 km./किमी.

  4. 4.5 km,/किमी.

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

Let distance = d km and scheduled time = t hours. At 3 km/hr: d/3 = t + 15/60 (15 minutes late). At 4 km/hr: d/4 = t - 15/60 (15 minutes early). Subtract: d/3 - d/4 = 30/60 = 0.5, so d/12 = 0.5, giving d = 6 km. Option B is correct. The time difference between slow and fast speed is 30 minutes total.

Multiple choice
  1. 15.5 Km/h किमी/घं

  2. 12.5 Km/h किमी/घं

  3. 14 Km/h किमी/घं

  4. 18 Km/h किमी/घं

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

Difference in speed = 4 km/hr, extra distance covered = 20 km. Time taken = 20/4 = 5 hours. Initial distance = 10 × 5 = 50 km. To cover 50 km in 4 hours: Speed = 50/4 = 12.5 km/hr. The time calculated is the time actually walked at both speeds.

Multiple choice
  1. I or II only

  2. II or III only

  3. II and (I or III)

  4. Any one is sufficient

  5. None of these

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

For the given data: 24 km upstream + 36 km downstream in 6 hours. Let boat speed = b, current speed = c. We have 24/(b-c) + 36/(b+c) = 6. Statement I: b = 10 km/hr gives 24/(10-c) + 36/(10+c) = 6, which solves to c = 2 km/hr - sufficient alone. Statement II: 36 km upstream + 24 km downstream in 6.5 hours gives a second equation, making two equations in two variables (b, c) - sufficient alone. Statement III: 48 km upstream in 6 hours means b-c = 8 km/hr; 48 km downstream in 4 hours means b+c = 12 km/hr. Solving gives c = 2 km/hr - sufficient alone. Each statement independently determines the current velocity.

Multiple choice
  1. Quantity I > Quantity II

  2. Quantity I ≥ Quantity II

  3. Quantity II > Quantity I

  4. Quantity II ≥ Quantity I

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

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

Quantity I: If downstream speed is 14 km/hr and upstream speed is 6 km/hr, then speed of swimmer in still water = (downstream + upstream)/2 = (14 + 6)/2 = 10 km/hr. Quantity II: Downstream distance 36 km in 6 hours gives downstream speed = 6 km/hr. Upstream distance 40 km in 8 hours gives upstream speed = 5 km/hr. Speed in still water = (6 + 5)/2 = 5.5 km/hr. Comparing: 10 > 5.5, so Quantity I > Quantity II.

Multiple choice
  1. 17.4

  2. 18.5

  3. 19.3

  4. 18.9

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

For equal distances at speeds 15 km/hr (upstream) and 24 km/hr (downstream), average speed = 2×15×24/(15+24) = 720/39 = 18.46 km/hr, approximately 18.5 km/hr. This is the harmonic mean of the two speeds.

Multiple choice
  1. 252 km./किमी.

  2. 256 km./किमी.

  3. 258 km./किमी.

  4. 249 km./किमी.

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

Let distance by bus = x km and by train = y km. Then x + y = 486 and x/78 + y/112 = 5.25. Substituting x = 486 - y into the time equation and solving: (486 - y)/78 + y/112 = 21/4. Multiplying by 34944 and simplifying gives 136y = 34272, so y = 252 km. The claimed answer is correct.

Multiple choice
  1. 16 kmph/(किमी./घंटा)

  2. 19 kmph/(किमी./घंटा)

  3. 17 kmph/(किमी./घंटा)

  4. 18 kmph/(किमी./घंटा)

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

Let original speed = x kmph. Time taken at x kmph = 36/x hours. At (x-6) kmph, time = 36/(x-6) hours. Difference is 1 hour: 36/(x-6) - 36/x = 1. Solving gives x=18. At 18 kmph, time is 2 hours. At 12 kmph, time is 3 hours - 1 hour more.

Multiple choice
  1. 2 hours 20 minutes

  2. 2 hours

  3. 1 hour 40 minutes

  4. 1 hour 20 minutes

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

Let original speed = v, original time = t. New speed = 1.2v. Since distance is same: v×t = 1.2v×(t-20). Dividing by v: t = 1.2(t-20). t = 1.2t - 24. 0.2t = 24. t = 120 minutes = 2 hours. When speed increases by 20%, time becomes 5/6 of original, saving 1/6 of the time.

Multiple choice
  1. Quantity I > Quantity II

  2. Quantity I ≥ Quantity II

  3. Quantity II > Quantity I

  4. Quantity II ≥ Quantity I

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

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

Quantity I: Let boat speed = b. Downstream (32 km) at b+2, upstream (32 km) at b-2. Total time 24 hours gives 32/(b+2) + 32/(b-2) = 24. Solving yields b = 4 km/hr. Quantity II: Total distance = 12 km in 5 hours gives average speed = 12/5 = 2.4 km/hr. Comparing: 4 > 2.4, so Quantity I > Quantity II.

Multiple choice
  1. Only II

  2. Only III

  3. I & either II or III

  4. All the three are necessary

  5. None of these

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

Let boat speed = b, stream speed = s. Upstream: (b-s) × 5 = distance. Downstream: (b+s) × 3 = distance. Statement III gives distance = 10 km. Setting up: 5(b-s) = 10 and 3(b+s) = 10. This gives b-s = 2 and b+s = 10/3. Solving: 2b = 2 + 10/3 = 16/3, so b = 8/3. Then s = 10/3 - 8/3 = 2/3 km/hr. All three statements are necessary.

Multiple choice
  1. Only I

  2. Only II

  3. Either I or II

  4. Neither I nor II

  5. Both I and II

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

Statement I: Average speed for two equal distances = 2×20×30/(20+30) = 24 kmph. Distance = 24×12 = 288 km. Statement II: Let distance = d, then d/30 - d/25 = 2, which gives d = 300 km. Either statement alone is sufficient.

Multiple choice
  1. 10 km.

  2. 12 km.

  3. 14 km.

  4. 8 km.

  5. 16 km.

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

Speed in still water = 8 km/h, current speed = 4 km/h. Downstream speed = 8+4 = 12 km/h. Upstream speed = 8-4 = 4 km/h. Let distance = d. Time upstream = d/4, Time downstream = d/12. Given: d/4 - d/12 = 2 hours. Solving: (3d - d)/12 = 2, so 2d/12 = 2, giving 2d = 24, so d = 12 km. Option B is correct.

Multiple choice
  1. 8 km/hr.

  2. 12 km/hr.

  3. 9 km/hr.

  4. 10.5 km/hr.

  5. 7.5 km/hr.

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

Ballu traveled 48 km 2 hours faster than planned. His actual speed was 1 km/hr more than intended for every 1 hr 15 min. Intended speed per 1.25 hrs = 10 km, so intended speed = 8 km/hr. Planned time = 48/8 = 6 hours. Actual time = 6 - 2 = 4 hours. Actual speed = 48/4 = 12 km/hr.

Multiple choice
  1. All

  2. Only I and II

  3. Only II and III

  4. Any two of them

  5. None of these

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

Data sufficiency analysis: Statement I gives car speed as bike speed + 10. Statement II gives 400/B - 400/C = 2. Statement III gives B/C = 4/5. Using I and II: C = B + 10, solving gives B = 40, C = 50. Using I and III: C = B + 10 and B = 0.8C gives B = 40, C = 50. Using II and III also gives C = 50. Thus any two statements together are sufficient.