A boy goes to school at a speed of 5 km/h and returns to the village at a speed of 4 km/h. If he takes 4 hr 30 min in all, what is the distance between the village and the school?

A 7 km

B 10 km

C 4 km

D 5 km

E 8 km

Correct Answer: Option B

Let the distance between village and school = x km

Time taken to travel from village to school at a speed of 5 km/hr = x/5 hr

Time taken to travel from school to village at a speed of 4 km/hr = x/4 hr

Given: total time taken = 4 hrs 30 minutes

\(= 4\;\frac{{30}}{{60}}\) hours

= 9/2 hrs

Thus, \(\frac{x}{5} + \;\frac{x}{4} = \;\frac{9}{2}\)

Or, x = 10 km

∴ The distance between village and school = 10 km