AS PER THE PROBLEM THE ANSWER IS TOTAL DISTANCE BETWEEN TWO POINTS IS 90 MILES.

120 miles.

if i walk 30 miles/hr i reach 1 hour before i.e

30(t-1) will give the exact distance

if walk 20 miles per hour i reach 1 hour late i.e

20(t+1) will give the exact distance

equating the distances gives time taken i.e 5 hours

and the dis b/w them is 120 miles

and the speed is 24miles/hour

(x/20)-(x/30) 1+1 //1hr late and 1 hr before//

then u get distance x 120miles....

and the speed at which it walks.....u consider the average speed then u get 24miles/hr......i.e.2xy/(x+y).