A cyclist rides 24 km at 16 kmph and further 36 km at 15 kmph. Find his average speed for the journey ?

A. 15.38 km/hr

B. 15.5 km/hr

C. 16 km/hr

D. None of these

Answer: Option A

Solution(By Examveda Team)

total distance travelled :
= (24 + 36) km
= 60 km
Total time taken :
$$\eqalign{ & = \left( {\frac{{24}}{{16}} + \frac{{36}}{{15}}} \right){\text{hrs}} \cr & = \left( {\frac{3}{2} + \frac{{12}}{5}} \right){\text{hrs}} \cr & = \frac{{39}}{{10}}{\text{ hrs}} \cr} $$
∴ Average speed :
$$\eqalign{ & = \left( {60 \times \frac{{10}}{{39}}} \right){\text{km/hr}} \cr & = \left( {\frac{{200}}{{13}}} \right){\text{km/hr}} \cr & = 15.38{\text{ km/hr}} \cr} $$