How do you find the perfect square between two numbers​

Need on this geometry question. explain how you did it.

You paid 28.00 for 8 gallons of gasoline. how much would you pay for 15 gallons of gasoline?

It took alice 5 5/6 hours to drive to her grandparents' house for . on the way home, she ran into traffic and it took her 7 3/8 hours. how much longer did the return trip take? write your answer as a proper fraction or mixed number in simplest form. the trip home took __hours longer. ?