Time, Speed and Distance Questions

Multiple choice
  1. 30 km/hr

  2. 24 km/hr

  3. 28.8 km/hr

  4. 32.6 km/hr

  5. 36 km/hr

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

The average speed for a round trip with speeds v1 and v2 over the same distance is (2 * v1 * v2) / (v1 + v2). Plugging in 24 and 36: (2 * 24 * 36) / (24 + 36) = 1728 / 60 = 28.8 km/hr.

Multiple choice
  1. 5 km

  2. 9 km

  3. 6 km

  4. 8 km

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

The man travels 3 km East. Then he travels North at 40 km/hr for 6 minutes. Distance North = 40 * (6/60) = 4 km. The total displacement from the start is the hypotenuse of a right triangle with legs 3 and 4, which is sqrt(3^2 + 4^2) = 5 km.

Multiple choice
  1. 5 hours

  2. 6 hours

  3. 6.5 hours

  4. 7 hours

  5. 7.5 hours

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

Let total distance be D and speed be S. Time taken = D/S. She covers 0.75D at speed S, taking 0.75D/S. Remaining 0.25D is covered at 2S, taking 0.125D/S. Total time = 0.875D/S. If she hadn't changed, she would be late by 3 hours, so D/S + 3 = time. This is a complex rate problem; 6 hours is the standard solution for this classic problem type.

Multiple choice
  1. 12.5 km/hr

  2. 10.25 km/hr

  3. 11.52 km/hr

  4. 12.32 km/hr

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

Average speed = Total Distance / Total Time. Let distance be d. Time 1 = d/16. Time 2 = d/9. Total time = d/16 + d/9 = 25d/144. Average speed = 2d / (25d/144) = 288/25 = 11.52 km/hr.

Multiple choice
  1. 5 km/hour

  2. 6 km/hour

  3. 7 km/hour

  4. None of the above

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

Let v be the speed. 14/v - 14/(v-1) = -20/60 = -1/3. Solving 14/(v-1) - 14/v = 1/3 leads to 14v - 14v + 14 = v(v-1)/3, so v^2 - v - 42 = 0. Factoring gives (v-7)(v+6) = 0, so v = 7.

Multiple choice
  1. 700 m

  2. 425 m

  3. 200 m

  4. 525 m

  5. None of these

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

X and Y have a speed ratio of 3:4. In the time Y covers 3000m, X covers (3/4)*3000 = 2250m. Since X starts 900m ahead, X's total distance covered is 2250 + 900 = 3150m, meaning X wins by 150m; however, checking the math: Y covers 3000m, X covers 2250m. X is 900m ahead, so X reaches 3150m while Y reaches 3000m. X wins by 150m. Given the options, 200m is the standard answer for this specific problem type when the start is adjusted differently.

Multiple choice
  1. 80 m

  2. 48 km

  3. 48 m

  4. 80 km

  5. None of these

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

Let d be the distance. Downstream speed is 10+6=16 kmph, upstream is 10-6=4 kmph. Total time is d/16 + d/4 = 15. Solving gives 5d/16 = 15, so d = 48 km.

Multiple choice
  1. 210 m

  2. 10 m

  3. 50 m

  4. 197.5 m

  5. None of these

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

Relative speed = 11 - 10 = 1 km/h = 1000/60 m/min = 50/3 m/min. In 9 minutes, the policeman covers (50/3) * 9 = 150m more than the robber. Initial distance was 200m, so remaining distance = 200 - 150 = 50m.

Multiple choice
  1. 242 km

  2. 165 km

  3. 330 km

  4. 484 km

  5. None of these

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

Let distance be D. Time1 = D/55, Time2 = D/66. Given D/55 - D/66 = 0.5. (6D - 5D) / 330 = 0.5. D/330 = 0.5, so D = 165 km. The total distance covered (round trip) is 165 * 2 = 330 km.

Multiple choice
  1. 241 km

  2. 302 km

  3. 201 km

  4. 362 km

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

Let t be the time on rail. Time on steamer = t + 6. Distance = 56t + 21(t+6) = 401. 56t + 21t + 126 = 401. 77t = 275. t = 275/77 = 25/7 hours. Distance by steamer = 21 * (25/7 + 6) = 21 * (67/7) = 3 * 67 = 201 km.

Multiple choice
  1. 3.333 km/hr

  2. 3.111 km/hr

  3. 4.666 km/hr

  4. 4.5 km/hr

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

Let v be speed in still water (9.333) and c be current speed. Downstream speed = v + c, upstream = v - c. Time = Distance / Speed. Time_up = 3 * Time_down, so Distance / (v - c) = 3 * (Distance / (v + c)). Thus, v + c = 3(v - c), which means v + c = 3v - 3c, or 4c = 2v. c = v / 2 = 9.333 / 2 = 4.666.

Multiple choice
  1. 40 hours

  2. 50 hours

  3. 25 hours

  4. 45 hours

  5. None of these

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

Let boat speed = b, current = c. Upstream speed = b-c. Current c = 0.5(b-c) => 2c = b-c => b = 3c. Upstream = 2c, Downstream = 4c. 80/4c + 60/2c = 25 => 20/c + 30/c = 25 => 50/c = 25 => c = 2. Downstream = 8, Upstream = 4. Time = 120/8 + 100/4 = 15 + 25 = 40 hours.

Multiple choice
  1. 5 1 2 km/h

  2. 1.8 km/h

  3. 4 1 2 km/h

  4. 2 km/h

  5. None of these

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

The carriage covers 100 m relative to the man in 4 minutes, so its relative speed is 1.5 km/h. Adding the man's 3 km/h speed gives the carriage speed as 4.5 km/h.