Quantitative Aptitude

Time, Speed and Distance

2,165 Questions
All Core formulas and unit conversion 441 Boats and streams effective speed 396 Relative speed, meetings, and overtaking 375 Average speed 362 Early and late arrival 321 Proportional relationships 202 Stoppage time per hour 35 Train and stationary or moving object crossing 17 Races and dead heats 16

Time, Speed and Distance Questions

Multiple choice

A boy walking at a speed of $10$ km/hr reaches his school $15$ minutes late. Next time he increases his speed by $2$ km/hr, but still, he is late by $5$ minutes. Find the distance of his school from his house.
  1. $10$ km
  2. $15$ km
  3. $20$ km
  4. $25$ km
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let d be distance. Time = d/10. Late by 15 min means d/10 = T + 15/60. At 12 km/hr, d/12 = T + 5/60. Subtracting: d/10 - d/12 = 10/60 = 1/6. (6d - 5d)/60 = 1/6. d/60 = 1/6, so d = 10 km.

Multiple choice

At his usual rowing rate, Rahul can travel $12$ miles downstream in a certain river in $6$ hours less than it takes him to travel the same distance upstream. But if he could double his usual rowing rate for his $24$ -mile round trip, the downstream $12$ miles would then take only one hour less than the upstream $12$ miles. What is the speed of the current in miles per hour?
  1. $1 \dfrac { 1 } { 3 }$
  2. $1 \dfrac { 2 } { 3 }$
  3. $2 \dfrac { 1 } { 3 }$
  4. $2 \dfrac { 2 } { 3 }$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Let v be rowing speed and c be current speed. 12/(v-c) - 12/(v+c) = 6. Also, 12/(2v-c) - 12/(2v+c) = 1. Solving these equations for c yields 8/3 or 2 2/3.

Multiple choice

Speed of motorboat in still water is $45\ km/h$. If the motorboat travels $80\ km$ along the stream in $1\ h 20\ min$, then the time taken by it to cover the same distance against the stream will be
  1. $4\ h 20\ min$
  2. $3\ h 40\ min$
  3. $2\ h 40\ min$
  4. $2\ h 55\ min$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Speed downstream = 80 / (4/3 h) = 60 km/h. Boat speed = 45 km/h, so stream speed = 15 km/h. Speed upstream = 45 - 15 = 30 km/h. Time = 80 / 30 = 8/3 hours = 2 hours 40 minutes.

Multiple choice

Vihang rowed upstream $48$kms. and back in $14$ hourse. He can row $4$kms. downstream in the same time as $3$kms. Find the flow of the stream
  1. $1$km/hr.
  2. $0.5$km/hr.
  3. $0.75$km/hr.
  4. $1.5$km/hr.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let the downstream and upstream speeds be d and u. Since 4 km downstream takes the same time as 3 km upstream, d/u = 4/3. Combining this with 48/u + 48/d = 14 gives d = 8 and u = 6, so the stream speed is (8 - 6)/2 = 1 km/hr.

Multiple choice

Choose the most appropriate option. A train which is moving at an average speed of $40$ kmph, reaches its destination on time. When its average speed reduces to $35$ kmph, then it reaches its destination $15$ minutes late. The distance travelled by the train is?
  1. $80$ kms
  2. $40$ kms
  3. $70$ kms
  4. $30$ kms
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let d be the distance. Time taken at 40 kmph is d/40, and at 35 kmph is d/35. The difference is 15 minutes, or 0.25 hours. So, d/35 - d/40 = 0.25. Solving this gives (8d - 7d)/280 = 0.25, so d = 280 * 0.25 = 70 km.