Question

Point $A$ and point $B$ are $421\text{km}$ and $562\text{km}$ away from the starting point in the same direction of a bike rally, respectively. A bike takes $6$ hours to reach point A, and it takes $9$ hours to reach point B from the starting point. Find the difference between the average speed noted at point A and B over the distance from the starting point.

• A. $7.722\dots \text{km/hr}$
• B. $70.166\dots \text{km/hr}$
• C. $6.633\dots \text{km/hr}$
• D. $62.444\dots \text{km/hr}$

Answer 1

The correct option is A $7.722\dots \text{km/hr}$

Average speed when the bike reaches point A.


Average speed when the bike reaches $A=\mathrm{70.166....}$

Average speed when the bike reaches point B.


Average speed when the bike reaches point B $=62.444\dots \text{km/hr}$

Difference in the speed
$=\mathrm{70.166...}-62.444=\mathrm{7.722...}\text{km/hr}$