25) E

Old speed = 30 kph
New speed = 30 – 3 = 27 kph

Let distance travelled on old route = D
Therefore, distance travelled by new route = D + 4
Let time taken on old route = T
Time taken on new route = 1.25T

Old distance
D = 30 x T = 30T —– (1)

New distance
D + 4 = 27 x 1.25T = 33.75T
D = 33.75T – 4 —– (2)

Using (1) and (2),
33.75T – 4 = 30T
33.75T – 30T = 4
3.75T = 4
T = 1.07 hours

D = 30T = 30 x 1.07 = 32.1 km
New distance = 32.1 + 4 = 36.1 km
This is close to 36 km so E is the answer.