Question

2. A covers half of this distance with 20 km/h and rest with
30 km/h. What is the average speed during the whole
joumey?
(a) 20 km/h
(b) 24 km/h
(c) 25 km/h
(d) 26 km/h
​

Answer 1

Answer:

Hey mate.

Here is your answer -

Step-by-step explanation:

Let the distance covered by him in half =x

Therefore, another half distance = x

Now- Time(1) =

$\frac{d}{s} = \: \frac{x}{20}$

Time(2) =

$\frac{d}{s} \: = \: \frac{x}{30}$

Therefore, Average Speed =

$\frac{total \: distance}{total \: time } \\ i.e \: \frac{x + x}{ \frac{x}{20} + \frac{x}{30} } \\ = \frac{2x}{ \frac{x}{50} } \\ = \: 2x \times \frac{50}{x} \\ = \: therefore \: x = \: 25 \: answer$

Hence, option c i. e, 25km/h is correct.

Hope it helps!!!