Time, Speed and Distance Questions

Multiple choice
  1. 30

  2. 45

  3. 60

  4. 72

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

Let Ts be time swimming, Th be time hiking. Ts = s/3, Th = h/6. Total distance s+h = 90. Th = 2 * Ts => h/6 = 2 * (s/3) => h/6 = 2s/3 => h = 4s. Substitute into s+h=90: s+4s=90 => 5s=90 => s=18. Then h=72.

Multiple choice
  1. 26 km/hr

  2. 16 km/hr

  3. 36 km/hr

  4. 30 km/hr

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

Let original speed be v and time be t. 96/v = t. New speed is v+1, new time is t-2. The distance is 96. Solving the system leads to v=16 km/hr.

Multiple choice
  1. 4

  2. 5

  3. 5k

  4. 7k

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

Distance s = 60t. Distance at 10k hours is 60 * 10k = 600k. Distance at 2k hours is 60 * 2k = 120k. The ratio is 600k / 120k = 5.

Multiple choice
  1. 15

  2. 30

  3. 24

  4. 28

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

Thief runs for 12s at 18m/s, distance = 216m. Policeman covers 864m. Time taken by policeman = t. Time taken by thief = t + 12. Distance of thief = 18 * (t + 12) = 216 + 18t. Total distance of thief = 216 + 18t = 864. 18t = 648, t = 36s. Speed of policeman = 864 / 36 = 24 m/s.

Multiple choice
  1. 2.4 km

  2. 3 km

  3. 2 km

  4. 2.8 km

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

Relative speed = 12 - 10 = 2 km/h. Time to catch = Distance / Relative speed = 0.4 km / 2 km/h = 0.2 hours. Distance covered by policeman = 12 km/h * 0.2 h = 2.4 km.

Multiple choice
  1. 6 kmph

  2. 8 kmph

  3. 10 kmph

  4. 12 kmph

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

Boat P's upstream speed is 4 kmph (40/10) and downstream speed is 8 kmph (40/5). The speed of boat P in still water is (8+4)/2 = 6 kmph, and the stream speed is (8-4)/2 = 2 kmph. Boat Q travels 30 km upstream in 5 hours, so its upstream speed is 6 kmph. Since Q's speed in still water minus the stream speed (2 kmph) equals 6 kmph, Q's speed in still water is 8 kmph.

Multiple choice
  1. 80 km

  2. 60 km

  3. 92 km

  4. 88 km

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

Let d be the distance from house to office. Time = d/16 + d/20 = 4.5 hours. (5d + 4d)/80 = 4.5 => 9d/80 = 4.5 => d = 4.5 * 80 / 9 = 40 km. Distance from house to friend's house = d + 1.2d = 2.2d = 2.2 * 40 = 88 km.

Multiple choice
  1. 4

  2. 3.75

  3. 5

  4. 4.5

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

Let v be the speed of the stream. Downstream speed is 7.5 + v, and upstream speed is 7.5 - v. Since time = distance / speed and time_up = 4 * time_down, we have 1 / (7.5 - v) = 4 / (7.5 + v). Solving this gives 7.5 + v = 30 - 4v, so 5v = 22.5, which means v = 4.5.

Multiple choice
  1. 0.6

  2. 0.5

  3. 0.4

  4. 0.9

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

Let v be swimmer speed and c be current speed. Distance A to C = (v-c) * (10/60). Distance C to B = (v+c) * (10/60). A to B = AC - CB = (v-c)/6 - (v+c)/6 = -2c/6 = -c/3. The magnitude is 200m = 0.2km. So c/3 = 0.2, c = 0.6 kmph.

Multiple choice
  1. 5 : 3

  2. 3 : 5

  3. 2 : 5

  4. 1 : 2

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

Let speed of boat be u and stream be v. Distance AB = d. Time AB + BA = d/(u+v) + d/(u-v) = 10. Time AC = d/(u-v) = 4. Solving these gives u/v = 5/3.

Multiple choice
  1. 2 2/3 mile/h

  2. 3 2/3 mile/h

  3. 5 2/3 mile/h

  4. 7 2/3 mile/h

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

Let v be rowing speed and c be current speed. The equations derived from the two scenarios (12/(v-c) - 12/(v+c) = 6 and 12/(2v-c) - 12/(2v+c) = 1) allow solving for c. Solving these yields c = 8/3 or 2 2/3 mph.