Time, Speed and Distance Questions

Multiple choice
  1. 1.5 km/hr

  2. 2.5 km/hr

  3. 3.5 km/hr

  4. 4.5 km/hr

  5. None of these

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

Let v be the stream speed. Upstream speed is 5-v, downstream is 5+v. Time taken upstream is 40/(5-v) and downstream is 40/(5+v). Given 40/(5-v) = 3 * 40/(5+v), so 5+v = 3(5-v), which simplifies to 5+v = 15-3v, 4v = 10, v = 2.5 km/hr.

Multiple choice
  1. 78 m/sec

  2. 75 m/sec

  3. 71 m/sec

  4. 67 m/sec

  5. 64 m/sec

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

Average speed = Total distance / Total time. Total distance = 440 m. Time taken for first 220 m = 220/70 = 22/7 sec. Time taken for return 220 m = 220/72 = 55/18 sec. Total time = 22/7 + 55/18 = (396 + 385) / 126 = 781/126 sec. Average speed = 440 / (781/126) = 55440 / 781 approx 71 m/sec.

Multiple choice
  1. 60 km/hr

  2. 55 km/hr

  3. 65 km/hr

  4. 75 km/hr

  5. 70 km/hr

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

Let original speed be V. Time saved by traveling 60 km at speed V instead of 0.8V is 12 minutes (0.2 hours). 60/(0.8V) - 60/V = 0.2. 75/V - 60/V = 0.2. 15/V = 0.2. V = 75 km/hr.

Multiple choice
  1. 19.44 km

  2. 49.07 km

  3. 20 km

  4. 26.75 km

  5. 31.3 km

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

Let t be the time in hours. The distance is 80t = 35t + 25, which simplifies to 45t = 25, so t = 25/45 = 5/9 hours. The actual distance covered is 35 * (5/9) = 175/9, which is approximately 19.44 km.

Multiple choice
  1. 960 m

  2. 1000 m

  3. 790 m

  4. 990 m

  5. 880 m

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

Let the speeds of A and B be vA and vB. Initially, vA = 1.2vB. Later, vB = 1.2vA. Since they finish at the same time, the time taken for each segment must balance. Solving the ratio of distances leads to A having run 960 m when B speeds up.

Multiple choice
  1. 5 1 2 km/hr

  2. 4 1 2 km/hr

  3. 7 1 2 km/hr

  4. None of these

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

Let the swimmer's speed in still water be v km/hr and the stream speed be 1.5 km/hr. Since downstream distance is twice upstream distance in the same time, (v + 1.5)/(v - 1.5) = 2, giving v = 4.5 km/hr.

Multiple choice
  1. 1 km/hour

  2. 2 km/hour

  3. 2.5 km/hour

  4. 3 km/hour

  5. 3.5 km/hour

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

Let boat speed be b and stream speed be s. Downstream speed = b+s, upstream = b-s. 48/(b+s) + 48/(b-s) = 14. Also, 4/(b+s) = 3/(b-s) implies 4(b-s) = 3(b+s), so 4b-4s = 3b+3s, b = 7s. Substituting b=7s into the time equation: 48/8s + 48/6s = 14, 6/s + 8/s = 14, 14/s = 14, s = 1.

Multiple choice
  1. 8 km/hour

  2. 10 km/hour

  3. 12 km/hour

  4. 13 km/hour

  5. 15 km/hour

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

Let speed be v and distance be d. d/v - d/(v+3) = 40/60 = 2/3. d/(v-2) - d/v = 40/60 = 2/3. d(3/(v(v+3))) = 2/3 => d = 2v(v+3)/9. d(2/(v(v-2))) = 2/3 => d = v(v-2)/3. Equating: 2v(v+3)/9 = v(v-2)/3 => 2v+6 = 3v-6 => v = 12.

Multiple choice
  1. Both I and II

  2. I and either II or III

  3. All I, II and III

  4. Data insufficient

  5. None of these

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

Statement I gives the downstream speed as 6 km/h. With statement II, the upstream speed is 3 km/h, so the still-water speed is 4.5 km/h. With statement III, the stream speed is one-third of the boat speed, which also determines the still-water speed from statement I, so I and either II or III are sufficient.

Multiple choice
  1. 130 km

  2. 150 km

  3. 180 km

  4. 200 km

  5. None of these

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

Total distance = 240 km. Y travels at 30 km/h for 120 km (4 hours) and 80 km/h for 120 km (1.5 hours). Total time = 5.5 hours. X travels d km at 40 km/h and (240-d) km at 60 km/h. d/40 + (240-d)/60 = 5.5. Multiply by 120: 3d + 2(240-d) = 660. 3d + 480 - 2d = 660. d = 180.