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 travels on a straight road from point $A$ to point $B$ in four hours, and then from point $B$ back to point $A$ in six hours. The distance between the two points is $240 km$. What is the car's average speed?
  1. $0 {km}/{h}$
  2. $48 {km}/{h}$
  3. $50 {km}/{h}$
  4. $60 {km}/{h}$
  5. $100 {km}/{h}$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Average speed = Total distance / Total time. Total distance = 240 (A to B) + 240 (B to A) = 480 km. Total time = 4 + 6 = 10 hours. Average speed = 480 / 10 = 48 km/h.

Multiple choice

A car moving with velocity which is measured each second and the data is recorded as per the table below. Velocity Time $0$ $0$ $2 {m}/{s}$ $1 s$ $4 {m}/{s}$ $2 s$ $6 {m}/{s}$ $3 s$ $8 {m}/{s}$ $4 s$ If the object stops accelerating at $4 s$ when its speed is $8 {m}/{s}$, Find out the distance it will travel between $4 s$ and $7 s$ .
  1. $8 m$
  2. $16 m$
  3. $18 m$
  4. $24 m$
  5. $32 m$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

After 4 seconds, the object stops accelerating, so its speed remains constant at 8 m/s. Over the next 3 seconds, the distance travelled is 8 × 3 = 24 m.

Multiple choice

Phoebe drives one-third of the distance from $A$ to $B$ at $x$ kilometers per hour, and she drives the other two-thirds of the distance at $y$ kilometers per hour. Calculate the Phoebe's average rate of speed, in kilometers per hour and in terms of $x$ and $y$ for the entire trip.
  1. $\dfrac {x+y}{2}$
  2. $\dfrac {x+2y}{3}$
  3. $\dfrac {2x+y}{3}$
  4. $\dfrac {xy}{x+y}$
  5. $\dfrac {3xy}{2x+y}$
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Average speed = Total distance / Total time. Let distance be 3D. Time = (D/x) + (2D/y) = (Dy + 2Dx) / xy. Average speed = 3D / ((Dy + 2Dx) / xy) = 3xy / (2x + y).

Multiple choice

When a $1700 kg$ car skids to a stop with initial speed $9 {m}/{s}$ on a flat road, it takes about $12 m$ to stop. Given that friction is the force allowing the car to decelerate, how much distance would the same car need to stop if it were initially moving at $15 {m}/{s}$?
  1. $33 m$
  2. $48 m$
  3. $20 m$
  4. $15 m$
  5. $18 m$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Work-energy theorem states that the work done by friction equals the change in kinetic energy. F*d = 0.5*m*v^2. Since F is constant, d is proportional to v^2. d2/d1 = (v2/v1)^2 = (15/9)^2 = (5/3)^2 = 25/9. d2 = 12 * (25/9) = 33.33 m.

Multiple choice

Two trains, each having a speed of $30 {km}/{h}$, are headed at each other on the same track. A bird flies off one train to another with a constant speed of $60 {km}/{h}$ when they are $60 km$ apart till before they crash. Find the distance covered by the bird and how many trips the bird can make from one train to other before they crash?
  1. $70 km$, infinity
  2. $60 km$, infinity
  3. $80 km$, infinity
  4. $90 km$, infinity
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Time until crash = Distance / Relative Speed = 60 / (30+30) = 1 hour. Bird speed = 60 km/h. Distance covered by bird = 60 km/h * 1 hour = 60 km. The number of trips is infinite because the bird's speed is constant and the distance between trains decreases continuously.

Multiple choice

If two trains are moving towards each other with velocities of 50 km/h and 60 km/h respectively. A fly flies to and fro in between them at a speed of 5 km/h. The initial distance between the trains is 220 km. How much distance will the fly cover before the trains crash?

  1. 5 km

  2. 10 km

  3. 15 km

  4. 20 km
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The trains are 220 km apart and closing at 50+60 = 110 km/h. Time until crash = 220 / 110 = 2 hours. The fly travels at 5 km/h for 2 hours, so distance = 5 * 2 = 10 km.

Multiple choice

A car moving with a speed of $40 km/hr$ can be stopped by applying breaks for $2$ km. If the same car is moving with a speed of $80 km/hr$, what is the minimum stopping distance? Assume constant retardation.
  1. $8 Km$
  2. $2 Km$
  3. $4 Km$
  4. $6 Km$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Stopping distance d is proportional to the square of the initial speed v^2 (since v^2 = 2ad). If speed doubles from 40 to 80, the stopping distance increases by a factor of 2^2 = 4. Thus, 2 km * 4 = 8 km.