From 8:25 to 30 seconds past 8:29 is 4.5 minutes.
This means she rode her bike 3/4 mile in 4.5 minutes.
Calculate her speed per mile:
1 mile / 0.75 = 1.333
4.5 minutes * 1.333 = 6 minutes per mile.
She needs to ride 3.42 miles, so multiply distance by speed:
3.42 miles x 6 minutes per mile = 20.52 minutes.
0.52 * 60 = 31.2 seconds.
This means it will take a total of 20 minutes and 31 seconds to get from her house to school.
She left at 8:25, add her travel time:
8:25 + 20 minutes and 31 seconds = 8:45 and 31 seconds.
This is sooner than the time school starts so she makes it on time.