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

Answer:

$f(x)=70-1.5x$ or $f(x)=-1.5x+70$

Step-by-step explanation:

Money taken to the fair = $90

Money spent to enter the fair = $5

Money spent on food =$15

Total he spent now is given by : $5+15=20$ dollars

Let the number of rides be = x

And he spends $1.50 on each ride, so total money spent on rides = $1.50x$

Total money including rides can be shown as:

$20+1.50x$

Now money left after this will be $90-(20+1.50x)$

=$70-1.50x$

Let f(x) denotes the function used to determine the money left after rides,

$f(x)=70-1.5x$ or $f(x)=-1.5x+70$

Answer 2

Easy, if he has $90 in ALL

and he spends $5 and $15

$20 in total

take, 90-20=70

So now he only has $70 left.

If each ride costs $1.50, then he's losing money.

So, y=-1.50x+70

So around the 47th ride he will have no more money.