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?

A.) f(x) = 1.5x + 70
B.) f(x) = -1.5x + 70
C.) f(x) = 1.5x - 70
D.) f(x) = -20x + 90

Answer 1

we are given with fixed rates of $5 for the fair entrance, and $15 for the food. The variable cost is $1.50 per ride. The initial money is $90. Hence the remaining money without considering the rides is 90-5-15 equal to 70. Thus, the function that expresses the money left is B.) f(x) = -1.5x + 70

Answer 2

Answer: Option 'B' is correct.

Explanation:

Since we have given that ,

Total money he takes while going to the fair = $90

Money he spends to enter the fair = $5

Money he spends on food =$15

Total he spent now is given by

`\$5+\$15=\$20`

Now, he spend on rides at the fair i.e. 1.50 per ride .

Let the number of rides be x

So, cost incurred on rides = 1.5x

So, the spending money can be expressed as

`20+1.50x`

Now, remaining money left to him after spending on x rides too is

`90-(1.50x+20)\\\\=90-1.50x-20\\\\=70-1.5x`

Let f(x) denotes the function used to determine the money he has left over after rides .

So it becomes

`f(x)=70-1.50x\\\\f(x)=-1.50x+70`