At the grocery store, an 8-inch cherry pie costs $4.39 and a similar 10-inch cherry pie cost $6.15. which is the better deal?

For the 8 inch pie you are paying about 55 cents per inch 
for the 10 inch pie you are paying about 61 cents per inch 
so the 8 inch pie is a better deal 

hope this helped 
oh and to get those numbers divide 4.39 by 8 and 6.15 by 10