Question

A car Travels first 30 km with a uniform speed of 60 km per hour and then next 30 km with a uniform speed of 40 km per hour calculate the total time of the journey and the average speed of the car

Answer 1

Ans 48km/hr first we calculate time then we calculate average speed

Answer 2

Answer:

The total distance covered in the journey is 1.25 km and average speed is 48 kmph.

Explanation:

Given:

First 30 km with 60 kmph speed

Next 30 km with 40 kmph speed

Total time of the journey = ?

Average speed of car = ?

★ Total Time =

Speed = Distance/Time

CASE I -

• Speed = 60 kmph
• Time = ??
• Distance = 30 km

⇒ 60 = 30/T

⇒ T = 30/60

⇒ T = 0.5 hours

Time in the first case = 0.5 hours

CASE II -

• Speed = 40 kmph
• Time = ??
• Distance = 30 km

⇒ 40 = 30/T

⇒ T = 30/40

⇒ T = 0.75

Time in the second case = 0.75 hours

Total Time =

⇒ 0.5 + 0.75

⇒ 1.25 hours

★ Average speed =

⇒ Total Distance/Total Time

⇒ (30 + 30)/(1.25)

⇒ 60/1.25

⇒ 48 kmph

The total distance covered in the journey is 1.25 km and average speed is 48 kmph.