Explanation:

- Let's denote the speed of train B as \( x \) km/h.

- The speed of train A is then \( x - 16 \) km/h.

- The time taken by train B to cover 384 km is \( \frac{384}{x} \).

- The time taken by train A to cover the same distance is \( \frac{384}{x - 16} \).

- It is given that train B takes 4 hours less than train A:

$$

\frac{384}{x - 16} - \frac{384}{x} = 4

$$

- Solving the equation, you find:

$$

\frac{384(x - x + 16)}{x(x - 16)} = 4

$$

$$

384 \times 16 = 4x(x - 16)

$$

$$

6144 = 4x^2 - 64x

$$

$$

4x^2 - 64x - 6144 = 0

$$

$$

x^2 - 16x - 1536 = 0

$$

- Solving this quadratic equation, we find one possible value for \( x \) as 48.

- The correct speed of train B is indeed 48 km/h.