Question

14. A car Covers first 2 km of the
total distance of 4 km with a speed
of 30 km/h and the renaming
distance of 2 km with a speed of 20
km/h. the average speed of the is *
A) 24 km/h
B) 25 km/h
C) 50 km/h
O D) 26 km/h
15. ​

Answer 1

Answer:

25 Km/h

Explanation:

Hope it helps you

Answer 2

$\LARGE{ \underline{\underline{ \sf{Required \: answer:}}}}$

GiveN:

• Total distance to be convered = 4 km

• The cars covers first 2 km with speed 30 km/h and the remaining distance with speed 20 km/h.

To FinD:

• Average speed of the car?

Step-wise-Step Explanation:

Average speed is calculated by:

• Total distance covered / Total time

We know the total distance but we don't know the total time. Time can be calculated by Distance / speed

Time taken with Speed - (1)

⇒ Time = Distance / Speed

⇒ Time = 2 km / 30 km/h

Time taken with Speed -(2)

⇒ Time = Distance / Speed

⇒ Time = 2 km / 20 km/h

Now putting the values of Total distance and Total time taken to get the average speed of the car:

⇒ $\rm{Avg. \: speed = \dfrac{4 \: km}{ \dfrac{2 \: km}{30 \: km {h}^{ - 1} } + \dfrac{2}{20 \: km {h}^{ - 1} } } }$

Now keeping the units aside for easier calculation and taking 2 common from the denominator:

⇒ $\rm{Avg. \: speed = \dfrac{4}{2( \dfrac{1}{30} + \dfrac{1}{20} )} }$

⇒ $\rm{Avg. \: speed = \dfrac{2}{ \dfrac{2 + 3}{60}} \: hr}$

⇒ $\rm{Avg. \: speed = \dfrac{2}{ \dfrac{5}{60} } }$

⇒ $\rm{Avg. \: speed = \dfrac{2 \times 60}{5} hr}$

⇒ $\rm{Avg. \: speed = \boxed{ \rm{24 \: km {h}^{ - 1}} }}$

Hence,

• The average speed of the car is 24 km/h