54 216
First look at the difference of the items sold between the 2 people. Clearly Lizzie sold 9 more boxes of peaches and earned 162 more dollars. We can solve and get that each box of peaches are worth 18 dollars. Then use what we found out --> 4 boxes of apples+1 boxes of peaches = 54 dollars. so 4 boxes of apples are worth 54-18=36 dollars. and thus each box of apples are worth 9 dollars.
Answer: each box of apples are wroth 9 dollars and each box of peaches are wroth 18 dollars. Done!