What is the average speed of a car which covers half the distance with a speed of 28 km/h and the other half with a speed of 84 km/h?

Correct option is A

Given:

Speed for first half = 28 km/h

Speed for second half = 84 km/h

Formula Used:

Average speed = $$\frac{2 \times x \times y}{x + y}$$​​

Solution: 

Average speed = $$\frac{2 \times 28 \times 84}{28 + 84}$$​​

​$$= \frac{2 \times 28 \times 84}{112}$$​​

​$$= \frac{4704}{112}$$​​

= 42 km/h