16. A florist is organizing a sale that offers carnations at a price of $4 for 10 and daisies at a price of $7 for 5. The florist plans to order a maximum of 500 flowers
for the sale and wants the revenue from the sale to be at least $400. If x is the
number of carnations and y is the number of daisies, and the florist sells all the
flowers ordered, which system of inequalities best describes this situation?