Question

A car travels first 50 km at a uniform speed of 25 km/h and next 60 kilometers at a speed of 20 km/hr Find average speed of the car?

Answer 1

Answer:

22 km/h

Explanation:

As per the provided information in the given question, we have :

• A car travels first 50 km at a uniform speed of 25 km/h.
• And, next 60 km at a speed of 20 km/hr.

We are asked to calculate the average speed of the car.

$\longmapsto \bf { Speed_{(avg)} = \dfrac{Total \; distance}{Total \; time} }$

Calculating total distance :

$\longmapsto \rm {Distance_{(Total)} = Distance_{(AB)} + Distance_{(BC)} }$

$\longmapsto \rm {Distance_{(Total)} = 50 \; km + 60 \; km }$

$\longmapsto \bf {Distance_{(Total)} = 110 \; km }$

∴ Total distance travelled is 110 km.

$\rule{200}2$

Calculating total time :

$\longmapsto \rm {Time_{(Total)} = Time_{(AB)} + Time_{(BC)} }$

• Time = Distance/Speed

$\longmapsto \rm {Time_{(Total)} = \dfrac{Distance_{(AB)}}{Speed_{(AB)}} + \dfrac{Distance_{(BC)}}{Speed_{(BC)}}}$

$\longmapsto \rm {Time_{(Total)} = \Bigg ( \cancel{\dfrac{50}{25}} + \cancel{\dfrac{60}{20}} \Bigg ) \; h}$

$\longmapsto \rm {Time_{(Total)} = \Big ( 2+ 3 \Big ) \; h}$

$\longmapsto \bf {Time_{(Total)} = 5 \; h}$

∴ Total time taken is 5 hours.

$\rule{200}2$

Calculating average speed :

$\longmapsto \rm { Speed_{(avg)} = \dfrac{Total \; distance}{Total \; time} }$

$\longmapsto \rm { Speed_{(avg)} = \cancel{\dfrac{110 \; km}{5 \; h} }}$

$\longmapsto \bf { Speed_{(avg)} = 22 \; kmh^{-1} }$

∴ Average speed of the car is 22 km/h.