Time and Distance
MCQs Math


Question:     An athlete takes 1 minute 20 second to complete a race of 1000 meter. Find the speed of the athlete in kilometre per hour.


Correct Answer  45 km/h

Solution And Explanation

[Strategy to solve the Question: (1) Calculate the speed in m/s after changing the given time in second and then change this speed into kilometre per hour. (2) change the distance into km and time into minute and second, and then calculate the speed using these units. This speed will be in the required kilometer per hour]

Given,

Distance = 1000 meter

Time = 1 minute 20 second

= 1 × 60 second + 20 second

⇒ Time = 80 second

Now we know that,

Speed = Distance/Time

Thus, speed of the given athlete

= 1000 meter /80 second

= 12.5 meter per second

⇒ Speed = 12.5 m/s

Conversion of speed from m/s to km/h

To convert meter per second (m/s) to kilometre per hour (km/h) we need to multiply m/s by 18 /5 .

Thus, 12.5 m/s

= 12.5 × 18 /5 km/h

= 45 km/h

Thus, speed of the given athlete = 45 km/h Answer

Second method to calculate the speed in km/h using distance given in meter and time given in second.

Here, given distance = 1000 meter

= 1000 /1000 km = 1 km

[∵ 1000 meter = 1 km. Thus, 1 meter = 1 /1000 km]

Thus, distance = 1 km

And, given time = 1 minute 20 second

= 1 × 60 second + 20 second

⇒ Time = 80 second

= 80 /60 × 60 hour

= 8 2/360 90 hour

= 2/90 hour

Calculation of speed in km/h using formula

Now we know that,

Speed = Distance/Time

Thus, the speed of the given athlete in km/h

= 1 km /2/90 hour

= 1 km × 90/2 hour

= 45 km/h

Thus, speed of the given athlete = 45 km/h Answer

[After observing the result obtained here, it is better to calculate the speed in m/s using the given units and after that change the speed from m/s to the required km/h.

The using of type of method depends upon the situation. ]

Calculation of speed using Unitary Method when time and distance are given]

Given, Distance = 1000 meter

And, Time = 1 minute 20 second

= 1 × 60 second + 20 second

⇒ Time = 80 second

∵ In 80 second, the distance covered = 1 km

∴ In 1 second, the distance covered = 1 km /80 second

= 12.5 m/s or 12.5 meter per second

Conversion of speed from m/s to km/h

To convert meter per second (m/s) to kilometre per hour (km/h) we need to multiply m/s by 18 /5 .

Thus, 12.5 m/s

= 12.5 m/1 s

= 12.5/1000 km /1/60 × 60 hour

= 12.5/1000 × 3600 km/h

= 12.5 × 3.6 km/h

= 45 km/h

Thus, speed of the given athlete = 45 km/h Answer


Similar Questions

(1) Find the distance covered by a moving object in 28 hours if it covers a distance of 92 km in 18 hours.

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

(3) Find the distance covered by a scooty in 22 hours if it covers a distance of 92 km in 12 hours.

(4) At a certain speed a car covers a distance of 46 km in 2 hours. How much distance will it cover in 3 hour?

(5) Find the distance covered by a cyclist in 21 hours if it covers a distance of 56 km in 11 hours.

(6) At a certain speed a scooty covers a distance of 34 km in 4 hours. How much distance will it cover in 5 hour?

(7) Find the distance covered by an athlete in 25 hours if it covers a distance of 58 km in 15 hours.

(8) By running at a speed of 42 km/h how much distance a car will cover in 5 second?

(9) At a certain speed a car covers a distance of 32 km in 2 hours. How much distance will it cover in 3 hour?

(10) Find the distance covered by a ball in 26 hours if it covers a distance of 72 km in 16 hours.


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