Question

Your friend has $80 when he goes to the fair. He spends $4 to enter the fair and $12 on food. Rides at the fair cost $1.25 per ride. Which function can be used to determine how much money he has left over after x rides?
f(x) = 1.25x + 64
f(x) = −16x + $80
f(x) = −1.25x + 64
f(x) = −1.25x − 64

Answer 1

spends $4 to enter the fair and $12 on food
$80 - $4 - $12 = $64 

fair cost $1.25 per ride
equation
1.25x = $64
or
f(x) = -1.25x + 64 

answer is C.
f(x) = −1.25x + 64