Time and Distance
Math MCQs

Question :    An athlete takes 15 hours to finish a race of 75 km. Calculate the speed of athlete in meter per second.

Correct Answer  1.389 m/s

Solution & Explanation

[Strategy to solve the Question: First of all, calculate the speed in km/h and then change this speed in meter per second. (2) change the distance into meter and time into second and then calculate the speed using these units, i.e. meter and second. This speed will be in the required meter per second]

Calculation of speed in km/h using formula

Given, Distance = 75 km

Time = 15 hour

We know that,

Speed = ^{Distance covered}/_Time

Therefore, speed = ^{75 5 km}/_{15 hour}

⇒ Speed = 5 km/h

Conversion of km/h into meter/second

We know that to convert km/h, we need to multiply the given speed in km/h by ⁵/₁₈

Thus, 5 km/h

= 5 × ⁵/₁₈

= ²⁵/₁₈

= 1.389 m/second

Thus, speed = 1.389 m/s Answer.

Calculation of speed in m/s using formula after changing the km to meter and time to hour

Given,

Distance = 75 km

= 75 × 1000 meter

[∵ 1 km = 1000 meter. Thus, to change the km into meter, we need to multiply the km by 1000]

⇒ Distance = 75000 meter

Time = 15 hour

= 15 × 60 × 60 second

[∵ 1 km = 1000 meter. Thus, to change the km into meter, we need to multiply the km by 1000]

⇒ Time = 54000 second

Now, we know that

Speed = ^Distance/_Time

⇒ Speed = ^{75000 meter}/_{54000 second}

= ⁷⁵ /₅₄ m/s

= 1.389 m/s

Thus, speed = 1.389 m/s Answer

Unitary Method to calculate the speed using distance and time

Given, Distance = 75 km

= 75 × 1000 meter

[∵ 1 km = 1000 meter. Thus, to change the km into meter, we need to multiply the km by 1000]

⇒ Distance = 75000 meter

Time = 5 hour

= 5 × 60 × 60 second

[∵ 1 hour = 60 × 60 second = 3600 second]

⇒ Time = 54000 second

∵ In 54000 second, the distance covered by the athlete = 75000 meter

∴ In 1 second, the distance covered by the athlete

= ^{75000 meter}/_{54000 second}

= ^{75 meter}/_{54 second}

= 1.389 meter per second

⇒ Speed = 1.389 m/s Answer

Similar Questions

(1) Find the distance covered by an athlete in 25 hours if it covers a distance of 76 km in 15 hours.

(2) By running at a speed of 19 km/h how much distance a bus will cover in 9 second?

(3) Find the distance covered by a scooty in 22 hours if it covers a distance of 52 km in 12 hours.

(4) By traveling a speed of 18 km/h, a bike completes a journey in 25 minute, then find the distance covered by him and how much time it will take cover a distance of 120 km?

(5) At a certain speed a cyclist covers a distance of 58 km in 3 hours. How much distance will it cover in 4 hour?

(6) At a certain speed a cyclist covers a distance of 26 km in 3 hours. How much distance will it cover in 4 hour?

(7) Find the distance covered by a cricket ball in 27 hours if it covers a distance of 86 km in 17 hours.

(8) By running at a speed of 22 km/h how much distance a motor bike will cover in 8 second?

(9) By running at a speed of 27 km/h how much distance an athlete will cover in 10 second?

(10) Find the distance covered by a car in 20 hours if it covers a distance of 56 km in 10 hours.