Interpret the following linear function model with the given context. Leslie wants to throw a birthday party at their local bowling alley. The space is $100 to rent with an additional charge of $15 per person attending. This scenario of total cost is modeled by the linear function: b (x) = 100 + 15x. Leslie gets a bill of $550 at the end of the evening. In addition to Leslie and Steve, how many other people attended this birthday party?

1 answer

To interpret the linear function \( b(x) = 100 + 15x \), we can break down its components in the context of Leslie's birthday party:

  • The term \( 100 \) represents the fixed cost to rent the bowling alley. This is the base cost, regardless of how many people attend the party.
  • The term \( 15x \) represents the variable cost that depends on the number of attendees, where \( x \) is the number of people attending the party (excluding Leslie and Steve). The \( 15 \) indicates that there is an additional charge of \( $15 \) for each person attending.

Now, Leslie received a bill of \( $550 \) at the end of the evening. We can set up the equation based on the total cost:

\[ b(x) = 550 \]

Substituting the linear function into this equation gives:

\[ 100 + 15x = 550 \]

Next, we can solve for \( x \):

  1. Subtract \( 100 \) from both sides:

\[ 15x = 550 - 100 \] \[ 15x = 450 \]

  1. Now, divide both sides by \( 15 \):

\[ x = \frac{450}{15} \] \[ x = 30 \]

Thus, \( x = 30 \) means that there were 30 people attending the party in addition to Leslie and Steve.

To find the total number of attendees, we need to add Leslie and Steve:

\[ \text{Total attendees} = x + 2 = 30 + 2 = 32 \]

In summary, in addition to Leslie and Steve, 30 other people attended the birthday party.