A man walks a certain distance with certain speed. If he walks 1/2 km an hour faster, he takes 1 hour
let the original rate of walking be x km/hr and the distance covered be y km.
therefore time taken to cover y km = distance/speed = y / x hr
if he walks 1/2 km/hr faster , he takes 1 hour less, therefore eq is:
if he walks 1 km / hr slower, he takes 3 more hours:
from eq(1) and eq(2):
since x is the speed , it can not be zero, therefore rate of walking = 4 km/hr
y = 48-12 = 36 km
thus the distance covered is 36 km.
hope this helps you.