Final answer:
The traveler's average food expenditure while on vacation was $40.75.
Step-by-step explanation:
To find the average food expenditure, we need to calculate the total amount spent on food and then divide it by the number of weeks. The traveler spent $25 the first week, $52 each for the next two weeks, and $34 the last week. Therefore, the total amount spent on food is $25 + $52 + $52 + $34 = $163. The average food expenditure is $163 divided by 4 (the number of weeks), which equals $40.75.