Question

A sports car travels 400m in 10 seconds. What is the speed in km per hour?

Answer 1

Answer:

The speed of sports car in km per hour is 144 km / hr.

Step-by-step explanation:

1 m = 1 / 1000 km

400 m = 400 / 1000 km

400 m = 4 / 10 km

400 m = 2 / 5 km      ...( i )

1 second = 1 / 60 mins

10 seconds = 10 / 60 mins

10 sec = 1 / 6 min

10 sec = 1 / 6 x 1 / 60 hr

10 sec = 1 / 360 hr       ...( ii )

It is given that the speed of sports car is 400m / 10 sec

                   

Substituting the values from ( i ) and ( ii ),

$\implies \dfrac{\frac{2}{5} \:km}{\frac{1}{360}\:hr}$

$\implies \dfrac{2}{5} \times \dfrac{360}{1} km / hr$

$\implies 2 \times 72 km/hr$

$\implies 144 km/hr$

Therefore the speed of sports car in km per hour is 144 km / hr.