Answer: Morgan will arrive at Town B at 5pm - 36 minutes = 4:24pm if she cycled at an average speed of 25km/h.
Step-by-step explanation: To solve this problem, we can use the formula: distance = speed x time.
We know that at 15km/h, Morgan reaches Town B at 6pm, and at 20km/h, she reaches Town B at 5pm.
We can use this information to find the distance between Town A and Town B and the time it takes to travel this distance at 25 km/h.
First, let's find the distance between Town A and Town B:
distance = speed x time
distance = 15 km/h x time
time = distance / 15 km/h
time = (distance / 15) hours
Since we know that when Morgan travel at 15km/h to reach town B at 6pm, we can use the time to calculate the distance:
time = 6pm - 5pm = 1hour
distance = 15 km/h x 1 hour = 15 km
Next, we can use this distance and the new speed 25km/h to calculate the arrival time:
time = distance / speed
time = 15 km / 25 km/h = 0.6 hours = 36 minutes
So, she will arrive at Town B at 5pm - 36 minutes = 4:24pm if she cycled at an average speed of 25km/h.
Please note that this calculation is assuming that the distance between Town A and Town B is a constant, and assuming that the time of arrival at 15km/h and 20km/h are accurate.