Question

a car travels 40km at a uniform speed of 40kmph and the next 40km at a uniform speed of 20kmph .find the average speed​

Answer 1

The answer given in the pic

Sorry for the inconvenience

 

Answer 2

Answer:

26.6 km/h

Explanation:

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

• A car travels 40 km at a uniform speed of 40 km/h.
• And, the next 40km at a uniform speed of 20 km/h.

We are asked to calculate the average speed.

In order to calculate the average speed, firstly we need to find the total distance travelled and total time taken.

Finding total distance travelled :

→ Total distance = 40 km + 40 km

→ Total distance = 80 km

Finding total time :

→ Total time = $\sf {t_1 + t_2 }$

• t_1 is time taken to cover first 40 km.
• t_2 is time taken to cover next 40 km.
• Time = Distance ÷ Speed

$\longrightarrow\sf {Total \;time = \Bigg \{\dfrac{40}{40} + \dfrac{40}{20} \Bigg \} \; h}$

$\longrightarrow\sf {Total \;time = \Bigg \{1 + 2 \Bigg \} \; h}$

$\longrightarrow\bf {Total \;time = 3 \; h}$

Therefore, total distance is 80 km and total time is 3 hours.

Now, finding the average speed :

→ Average speed = Total distance ÷ Total time

→ Average speed = 80 km ÷ 3 h

→ Average speed = 26.6 km/h

∴ Average speed of the car is 26.6 km/h.