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 car is moving with a speed of $72 {km}/{h}$ towards a hill. Car blows horn at a distance of $1800 m$ from the hill. If echo is heard after $10 s$, the speed of sound (in ${m}/{s}$) is
  1. $300$
  2. $320$
  3. $340$
  4. $360$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Distance traveled by sound = 2 * distance to hill - distance traveled by car in 10s. Distance to hill = 1800m. Car speed = 72 km/h = 20 m/s. In 10s, car moves 200m. Sound travels 1800 + (1800 - 200) = 3400m. Speed of sound = 3400m / 10s = 340 m/s.

Multiple choice

A road runs midway between two parallel rows of buildings. A motorist moving with a speed of 36 km/hour sounds the horn. He hears the echo one second after he has sounded the horn. The distance between the 2 rows of buildings is (Velocity of sound is 330 m/s)

  1. 300 m

  2. 150 m

  3. 1080 m

  4. 330 m
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Speed of motorist = 36 km/hr = 10 m/s. In 1 second, the motorist moves 10 meters. The sound travels to the wall and back in 1 second. Distance sound travels = 330 * 1 = 330 m. Let d be the distance from the road to one wall. The sound travels (d - 10) + (d + 10) = 2d. So 2d = 330, d = 165. Total distance between walls = 2d = 330 m.

Multiple choice

A thief robs a house at $12$ midnight and as soon as he leaves the house the house owner realises of the robbery in the house. After $10$ minutes, he rings the alert alarm and the security guards of the house start running after the thief to catch him. If the speed of the thief is $30$ km/hr and that of the security guard is $20$ km/hr, what time will the guards catch the thief?
  1. $00.30$ hrs
  2. $00.40$ hrs

  3. cannot be determined

  4. Never catch the thief
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The thief is moving at 30 km/hr and the guard at 20 km/hr. Since the thief is faster than the guard, the distance between them will increase over time rather than decrease. Therefore, the guard will never catch the thief.

Multiple choice

$A$ and $B$ start simultaneously from a certain point in North and South direction on motorcycles. The speed of $A$ is $80$ km/hr and that of $B$ is $65$ km/hr. What is the distance between $A$ and $B$ after $12$ minutes?
  1. $14.5$ km
  2. $29$ km
  3. $36.2$ km
  4. $39$ km
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A and B move in opposite directions (North and South). Relative speed = 80 + 65 = 145 km/hr. Time = 12 minutes = 12/60 = 1/5 hours. Distance = Speed * Time = 145 * (1/5) = 29 km.

Multiple choice

A father and his son start at a point A with spends of $12$ kmph and $18$ kmph respectively, and reach another point B. If his son starts $60$ minutes after his father at A and reaches B $60$ minutes before his father, what is the distance between A and B?
  1. $90\ km$
  2. $72\ km$
  3. $36\ km$

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

If the distance is D, the father's travel time is D/12 and the son's is D/18. Because the son starts 1 hour later and arrives 1 hour earlier, D/12 = D/18 + 2, which gives D = 72 km.

Multiple choice

After covering a distance of $30\ km$ with a uniform speed there is some defect in a train engine and therefore its speed is reduced to $\dfrac{4}{5}$ of its original speed. Consequently the train reaches its destination late by $45$ minutes. Had it happened after covering $18$ kilometers more the train would have reached $9$ minutes earlier, find the speed of the train and the distance of journey.
  1. Speed $=40 km/hr$, Distance $=160 km$
  2. Speed $= 20 km/hr$, Distance $= 100 km$
  3. Speed $=30 km/hr$, Distance $= 120 km$
  4. Speed $=35 km/hr$, Distance $=140 km$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let v be speed and d be distance. Using the time difference equations, we solve for v and d. The system yields v = 30 km/hr and d = 120 km.

Multiple choice

Soniya and Priyanka started from Amethi and Bellari , which are 645 km apart. They meet after 15 hours. After their meeting , Sonia increased her speed by 3 km/hr and Priyanka reduced her speed by 3 km/hr, they arrived at Bellari abd Amethi respectively at the same time. What is their initial speed?
  1. $24\ and\ 23$
  2. $21\ and\ 23$
  3. $20\ and\ 23$
  4. $21\ and\ 25$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Their initial speeds add to 645/15 = 43 km/hr. After meeting, the equal-time condition gives p/(s + 3) = s/(p - 3), which simplifies to p - s = 3. Solving s + p = 43 and p - s = 3 gives speeds 20 km/hr and 23 km/hr.