Tony is going to buy fruit for smoothie. He wants raspberries, r, that are $4 a carton and strawberries, s, that are $2a carton. write an equation to represent all the combinations of fruit if Tony has $18 to spend.

4r + 2s = 18

Step-by-step explanation:

creating an equation

since raspberries are $4 a carton and strawberries are $2 a carton.

we can use variable to represent both strawberries and raspberries

strawberries = s

raspberries = r

since the total of both the items are $18. we can create this formula:

4r + 2s = 18

this means 4 multiplied by the number of cartons of raspberries + 2 * the number of cartons of strawberries = $18