Final answer:
The average check in a restaurant is calculated by dividing the sales revenue for a period by the number of guests served during that period.
Step-by-step explanation:
The average check in a restaurant is calculated by dividing the sales revenue for a period by the number of guests served during that period. This gives us the average amount of money spent per guest. For example, if the sales revenue for a month is $10,000 and 500 guests were served during that month, then the average check would be $20 ($10,000 / 500 = $20).