Question 501663
Let d be the distance 
X m/hr be the walking speed
Y m/hr be the speed in bike
X = Y -7 -> equation 1

distance = speed * time

Walking: 
   d = X*40/60 = 2*X/3

In Bike:
    d = Y * 12/60 = Y/5

Equation above ,
 2*X/3 = Y/5

10X = 3Y

from equation 1,
   10(Y-7) = 3Y
     7Y = 70
    Y = 10 miles/hr

Distance = 10*1/5 = 2 miles