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

Answer: Option A

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