Deeksha travels in her car from City A to City B at a speed of 120 km/h, and while coming back by the same route from City B to City A she travels at a speed of 130 km h . Find Deeksha’s average speed during the whole journey

Correct option is C

Given:

Speed from City A to City B = 120 km/h

Speed from City B to City A = 130 km/h 

Formula Used : 

$$\text{Average speed} = \frac{2 \times \text{Speed}_{A \to B} \times \text{Speed}_{B \to A}}{\text{Speed}_{A \to B} + \text{Speed}_{B \to A}}$$ 

Solution: 

$$\text{Average speed} = \frac{2 \times 120 \times 130}{120 + 130}$$ 

= $$\frac{2\times15600}{250}$$ 

= $$\frac{31200}{250}$$ 

= $$\frac{3120}{25}$$ 

= $$\frac{624}5$$ 

= 124.8 km/h