Final answer:
To calculate the number of sandwiches needed for 60 persons, a proportion is set up based on 12 sandwiches being prepared for 8 persons. By solving the proportion (8/12 = 60/x), it is determined that 90 sandwiches must be prepared to serve 60 persons.
Step-by-step explanation:
If 12 sandwiches are prepared for 8 persons, to find out how many sandwiches must be prepared for 60 persons, we can set up a proportion to solve the problem. The number of sandwiches is directly proportional to the number of persons. Therefore, if x is the number of sandwiches needed for 60 persons, our proportion would be:
8 persons / 12 sandwiches = 60 persons / x sandwiches
To find the value of x, we cross multiply and solve:
8 * x = 60 * 12
x = (60 * 12) / 8
x = 720 / 8
x = 90
Therefore, 90 sandwiches must be prepared for 60 persons.