1. **State the problem:** A man drives 240 km from A to B at 120 km/h and returns from B to A at 80 km/h. We need to find his average speed for the whole journey. 2. **Formula for average speed when distances are equal:** $$\text{Average speed} = \frac{2 \times v_1 \times v_2}{v_1 + v_2}$$ where $v_1$ and $v_2$ are the speeds for each part of the journey. 3. **Apply the formula:** $$\text{Average speed} = \frac{2 \times 120 \times 80}{120 + 80}$$ 4. **Calculate the denominator:** $$120 + 80 = 200$$ 5. **Calculate the numerator:** $$2 \times 120 \times 80 = 19200$$ 6. **Calculate the average speed:** $$\frac{19200}{200} = 96$$ 7. **Answer:** The average speed for the whole journey is **96 km/h**.