Let:
r = regular route distance
v = regular route speed
Scheduled time = r/v
Detour route:
distance = r + d
speed = v + s
Detour time = (r + d)/(v + s)
We need to know whether:
(detour time) − (regular time) > 2
Statement (1):
The average speed differed by no more than 20 km/h.
So:
|s| ≤ 20
No information about distances.
Example 1:
Regular: 100 km at 100 km/h → 1 hour
Detour: 500 km at 80 km/h → 6.25 hours
Difference > 2 hours
Example 2:
Regular: 100 km at 100 km/h → 1 hour
Detour: 120 km at 100 km/h → 1.2 hours
Difference < 2 hours
Not sufficient.
Statement (2):
Distance differed by no more than 40 km.
So:
|d| ≤ 40
No information about speed.
Example 1:
Regular: 100 km at 100 km/h → 1 hour
Detour: 140 km at 10 km/h → 14 hours
Difference > 2
Example 2:
Regular: 100 km at 100 km/h → 1 hour
Detour: 140 km at 140 km/h → 1 hour
Difference = 0
Not sufficient.
Together:
Distance changes by at most 40 km and speed changes by at most 20 km/h.
Still not enough.
Example 1:
Regular: 100 km at 100 km/h → 1 hour
Detour: 140 km at 80 km/h → 1.75 hours
Difference < 2
Example 2:
Regular: 100 km at 20 km/h → 5 hours
Detour: 140 km at 1 km/h → 140 hours
Speed differs by 19 km/h, distance differs by 40 km
Difference > 2
Both satisfy the statements but give different answers.
Therefore, the statements together are not sufficient.
Answer: E