Time, Speed and Distance Questions

Multiple choice
  1. 94 km

  2. 78 km

  3. 84 km

  4. 88 km

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

Upstream speed = 18 - 2 = 16 km/h. Downstream speed = 18 + 2 = 20 km/h. Distance upstream = 16 × 3 = 48 km. Distance downstream = 20 × 2 = 40 km. Total distance = 48 + 40 = 88 km.

Multiple choice
  1. 45

  2. 36

  3. 52

  4. 30

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

They start 40 floors apart (51-11) and close the gap at combined speed 120 floors/min. Time to meet is 40/120 = 1/3 min. Subham travels 57×1/3 = 19 floors up from floor 11, reaching floor 30. Option A (45) is above both starting positions. Option B (36) and C (52) ignore the relative motion.

Multiple choice
  1. 60

  2. 150

  3. 120

  4. 90

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

Distance = Speed × Time = 90 × (35/60) = 52.5 km. To cover 52.5 km in 21 minutes, needed speed = 52.5 / (21/60) = 52.5 × 60/21 = 150 km/hr. Increase needed = 150 - 90 = 60 km/hr. Use consistent units (convert minutes to hours) and relate distance = speed × time.

Multiple choice
  1. $\(\frac{120}{7}\)$
  2. $\(\frac{240}{7}\)$
  3. $\(\frac{360}{7}\)$
  4. $\(\frac{60}{7}\)$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let distance be D km and on-time speed be S km/h. At 40 km/h, reaches 30 min early: D/40 = T - 0.5. At 30 km/h, reaches 30 min late: D/30 = T + 0.5. Subtracting gives D/30 - D/40 = 1, so D(1/30 - 1/40) = 1, D(4/120 - 3/120) = 1, D(1/120) = 1, so D = 120 km. Then T = 120/40 + 0.5 = 3.5 hours. Speed to be on time = 120/3.5 = 240/7 ≈ 34.29 km/h.

Multiple choice
  1. Only I and II

  2. Only II and III

  3. All I, II and III

  4. Cannot be answered even including all three statements

  5. None of these

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

Let speeds be 4x and 5x km/hr. From III: 5x - 4x = 60, so x = 60. Speeds: 240 km/hr, 300 km/hr. From II: Time difference = 1 hr. If distance = D, then D/240 - D/300 = 1. D(1/240 - 1/300) = 1. D(60/72000) = 1, so D = 1200 km. All three statements are needed. Statement II and III alone don't give initial speed ratio. Statement I and II alone give relationship but not actual values.

Multiple choice
  1. 100 km/h

  2. 150 km/h

  3. 160 km/h

  4. 200 km/h

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

Distance = Speed × Time. Since distances are equal: S₁ × 0.6 = S₂ × 1. Given S₂ = 96 km/hr, S₁ × 0.6 = 96 × 1 = 96, so S₁ = 96/0.6 = 160 km/hr. Option A (100) incorrectly adds 40% to 96. Option B (150) uses 96 × 1.5625 incorrectly. Option D (200) mistakenly uses 96 × 2. This tests the inverse relationship between speed and time for constant distance.

Multiple choice
  1. 2: 5

  2. 3: 5

  3. 4: 7

  4. 7: 3

  5. 3: 7

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

When trains travel toward each other, they travel for the same time until meeting. One train covers 150 km, the other covers 400 - 150 = 250 km. Since time is constant, the ratio of speeds equals the ratio of distances: 150:250 = 3:5. The slower train traveled 150 km and the faster traveled 250 km.

Multiple choice
  1. 4

  2. 5

  3. 8

  4. 9

  5. 6

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

Let boat speed = b, stream speed = s. Downstream speed = b + s, Upstream speed = b - s. Given: b - s = (b + s) - 6, so b - s = b + s - 6, giving 2s = 6, so s = 3 km/hr. Boat speed b = 21 km/hr. Upstream speed = 21 - 3 = 18 km/hr. Time for 108 km upstream = 108/18 = 6 hours. Option E is correct.

Multiple choice
  1. 2

  2. 3

  3. 4

  4. 5

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

Let v be the boat's speed in still water. Downstream speed is v+1 km/h and upstream speed is v-1 km/h. The total time equation is 4/(v+1) + 4/(v-1) = 3 hours. Solving gives 8v = 3(v²-1), which yields v = 3 km/h. The negative solution is rejected as speed cannot be negative.

Multiple choice
  1. 120

  2. 180

  3. 175

  4. 150

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

Distance AB = 60 km. They first meet 15 km from B, meaning the faster person covers 60 + 15 = 75 km while the slower covers 60 - 15 = 45 km in the same time. Their speed ratio is 75:45 = 5:3. Let speeds be 5x and 3x. Difference is 2x = 60, so x = 30. Faster speed = 5 × 30 = 150 km/h. This is a standard relative speed problem with return journey.