Answer:
The average spent at his store is of $37.60.
The average spent at his competitor's store is of $48.53.
Step-by-step explanation:
Average of a data set:
The mean of a data set is the sum of all values divided by the number of values.
His store:
15 orders.
Prices of: 41, 38, 19, 30, 21, 53, 34, 34, 37, 29, 50, 43, 57, 28, 50
The average is:

The average spent at his store is of $37.60.
Store of the competitor:
15 orders
Prices of: 86, 15, 75, 40, 51, 60, 27, 45, 112, 7, 65, 31, 18, 27, 69
The average is:

The average spent at his competitor's store is of $48.53.