Sandy rides his bike to school in 15 minutes. Riding is ten kilometres faster than walkingWhen hel walks it takes 45 minutesHow far away is the school?

The answer is 3.75 km.. Take walking speed as xkm/hr. then x km/hr takes 45 min(3/4 hr) (x+10)km/hr takes 15 min(1/4hr) equating, we get x as 5km/hr. 1 hour by walk he can travel 5 km,, then by walkinfor 45 min he can travel 3.75 km..