You have to divide the bottles of apple juice by the number of glasses to get the amount of juice one glass carries. ( 48/8) which is 6. Then when you divide the bottles of orange juice by the number of glasses to get the the amount of juice a glass carries. (37/7) which is 5.
First you figure out the unit rate by dividing 360 by 6 which is 60. So that's 60 miles per hour. Now multiply 60 by 7 to find out how many miles she will drive in 7 hours. When you multiply you get 420.