Without even reading the rest of the question, you should be able to tell that the answer is 3x + 3.50y ≤ 50.
This symbol ≤ means "less than or equal to." In the question, it mentions that he has a maximum of $50 to spend which tells us that the cost has to be less than $50 but can be exactly $50.
You can then use the other information to verify your answer. Lilies are represented by the variable
and costs $3.00 each, so it makes sense that the formula says
. Roses on the other hand is represented by the variable
and costs $3.50 each, so it makes sense that the formula says
.