slope intercept

Question

Your friend has $90 when he goes to the fair. He spends $5 to enter the fair and $15 on food. Rides at the fair cost $1.50 per ride. Which function can be used to determine how much money he has left over after x rides?

Answer 1

$1.50 for 6 rides is 1.50(6), right? Add $20 for entrance and food and 1.50(6) + 20 is spent.

After $20 is spent, there's 90-20 = $70 left for food.

f(x) = 70 - 1.50x