A man travels for 5 hours 15 minutes. If he covers the first half of the journey at 60 km/h and rest at 45 km/h. Find the total distance travelled by him.

A. 189 km

B. 378 km

C. 270 km

D. $$1028\frac{6}{7}$$  km

Answer: Option C

Solution(By Examveda Team)

Average speed :
$$\eqalign{ & = \frac{{2 \times 60 \times 45}}{{60 + 45}} \cr & = \frac{{1080}}{{21}}{\text{ km/hr}} \cr} $$
Time :
$$\eqalign{ & = 5 + \frac{1}{4}{\text{ hr}} \cr & {\text{ = }}\frac{{21}}{4}{\text{ hr}} \cr} $$
Distance travelled :
$$\eqalign{ & {\text{ = }}\frac{{1080}}{{21}} \times \frac{{21}}{4} \cr & = 270{\text{ km}} \cr} $$