If the speed is x and the distance is 1, the time required is 1/x under the condition of constant vehicle speed.

List the equations according to the meaning of the question:

( 1/x)- 1 = 1÷[( 1+20%)x]

Solution: x= 1/6,

If you want to arrive two hours earlier, let's assume that the speed is higher than the original Y, then

( 1/x)-2 = 1÷[( 1+y)x]

Because x= 1/6, substitute the above formula to get:

y=50%

Hope to adopt