Hi there!
So, in 4 minutes and 30 seconds, she was able to go .75 miles. At this time, it is 30 seconds past 8:29. Now, she'll go another .75 miles. At this time, it is 8:34 and she has gone 1 1/2 miles. Then, she'll go another .75 miles. At this time, it is 30 seconds past 8:38 and she has gone 2.25 miles. Then, she'll go another .75 miles. At this time, it is 8:43 and she has gone 3 miles. Lastly, she'll reach her school at approximately 8:47. The answer is yes, she can make it to school on time without increasing her speed.
Hope this helps!! :)
If there's anything else that I can help you with, please let me know!