Answer:
she rides her bike at a rate of 8mph during the second part of the trip.
Explanation:
for the first part of the trip, she rides 18 miles in 2 hours which means that she bikes at a rate of 9 miles per hour.
subtracting 18 from 58 gives us the distance she biked during the second part of her trip (which is 40 miles). subtracting 2 from 7 gives us that she biked for 5 more hours. Putting this together means she biked 40 miles in 5 hours.
Now divide miles by hours
to get your average rate of change for the second part of the trip.