Question

A car travels first 20 km with the speed of 40 kmph and next 40 km with the speed of 80 kmph . Find the average speed ​

Answer 1

Answer:

Correct Question: A car travels the first 20km with a speed of 40kmh-1 and the next 40km with a speed of 80kmh-1. Find the average speed.

Explanation:

For first 20 km,

Speed of the car = 40 kmh⁻¹

Distance travelled = 20 km

⇒ Time =  hour

⇒ Time = 30 minutes

For next 40 km,

Speed of car = 80 kmh⁻¹

Distance travelled = 40 km

Time taken =  

⇒ Time =  

⇒ Time =  hour

⇒ Time = 30 minutes

__________________________________

Now,

Total distance travelled = (20 + 40) km

⇒ Distance = 60 km

Total time taken = (30 + 30) minutes

⇒ Time taken = 1 hour

Hence, the average speed is 60 kmh⁻¹.

Answer 2

Question

A car travels the first 20 km with a speed of 40 km/h-1 and the next 40 km with a speed of 80 km/h-1. Find the average speed.

SOLUTION=>

Given,

Speed of car = 40 kmh^-1

Distance travelled by car = 20 km

Time = ?

Now we have to find time.

Time = Distance / Speed

t = 20 / 40

t = 1/2 h

=> 30 min