Final answer:
The situation can be represented by a system of equations: x + y = 18 and 2x + 5y = 60, where x represents the number of carnations and y represents the number of roses.
Step-by-step explanation:
The situation can be represented by the following system of equations:
x + y = 18 - This equation represents the total number of flowers Juan bought, where x stands for the number of carnations and y stands for the number of roses.
2x + 5y = 60 - This equation represents the total amount spent by Juan on the flowers, where 2 is the cost of each carnation and 5 is the cost of each rose.