Question

A bike travels 80 km with the speed of $40kmph$ and another 60 km with the speed of $30kmph$. Find the average speed of the bike.

• A. $30kmph$
• B. $35kmph$
• C. $40kmph$
• D. $45kmph$

Answer 1

The correct option is B

$35kmph$

We know, speed $=\frac{distance}{time}$

So, time taken for the first half of the journey:

$T_1=\frac{distance}{speed}=\frac{80}{40}=2hr$

Time taken for the second part of the journey

$T_2=\frac{distance}{speed}=\frac{60}{30}=2hr$

Total time $=T_1+T_2=2+2=4hr$

Total distance covered = 80 + 60 = 140 km

Average speed $=\frac{\text{total distance}}{\text{total time}}=\frac{140}{4}=35kmph$