The question in the image reads:

Question:

A vehicle travels from city A to city B at a speed of 60 km/h and returns from city B to city A.

If the vehicle's average speed during the entire journey is 48 km/h, what was its speed while returning from city B to city A?

Answer choices: A) 20
B) 25
C) 30
D) 40
E) 50

Solution:

Let the distance between city A and city B be $d$ km.

1. Time for the trip from A to B: The speed from A to B is $60 \, \text{km/h}$.
   Time taken:
   $t_1 = \frac{d}{60}$

2. Let the speed from B to A be $v \, \text{km/h}$.
   Time taken for the return trip (B to A):
   $t_2 = \frac{d}{v}$

3. Average speed formula:
   The average speed for the entire trip is given as $48 \, \text{km/h}$, and the formula for average speed is:
   $\text{Average Speed} = \frac{\text{Total Distance}}{\text{Total Time}}$

   The total distance for the round trip is $2d$, and the total time is $t_1 + t_2$. Substituting these:
   $48 = \frac{2d}{\frac{d}{60} + \frac{d}{v}}$

4. Simplify the equation:
   Factor out $d$:
   $48 = \frac{2}{\frac{1}{60} + \frac{1}{v}}$

   Combine the denominators:
   $\frac{1}{60} + \frac{1}{v} = \frac{v + 60}{60v}$