Sonya’s book has 400 pages. how many pages are in 1% of the book?

X/400 cross multiplied by 1/100 means 1% of the book is 4 pages. 

Just divide the miles travelled by the time:
115/15= 7.67 miles per minute
Then convert the minutes to hours by multiplying the 7.67 and the 1 by 60 (remember that "per" indicates "over one", so 7.67 miles/1 minute):
7.67*60/1*60= 460.2 miles per hour.