High School

For groups of 25 or more people, a museum charges [tex]$21[/tex] per person for the first 25 people and [tex]$14[/tex] for each additional person. Which function [tex]f[/tex] gives the total charge, in dollars, for a tour group with [tex]n[/tex] people, where [tex]n \geq 25[/tex]?

A. [tex]f(n) = 14n + 175[/tex]
B. [tex]f(n) = 14n + 525[/tex]
C. [tex]f(n) = 35n - 350[/tex]
D. [tex]f(n) = 14n + 21[/tex]

Answer :

To solve the problem of determining which function [tex]\( f \)[/tex] represents the total charge for a tour group with [tex]\( n \)[/tex] people, where [tex]\( n \geq 25 \)[/tex], let's break it down step-by-step.

1. Determine the cost for the first 25 people:
- The museum charges \[tex]$21 per person for the first 25 people. So, the cost for these 25 people is:
\[ 25 \times 21 = 525 \text{ dollars} \]

2. Determine the cost for additional people beyond the first 25:
- For each additional person (beyond the 25), the cost is \$[/tex]14 per person.

3. Express the total cost as a function of [tex]\( n \)[/tex]:
- If there are [tex]\( n \)[/tex] people, the number of additional people beyond the first 25 is [tex]\( n - 25 \)[/tex].
- The cost for these additional people is [tex]\( 14 \times (n - 25) \)[/tex].

4. Calculate the total cost function:
- The total cost [tex]\( f(n) \)[/tex] for [tex]\( n \)[/tex] people (where [tex]\( n \geq 25 \)[/tex]) is the sum of the cost for the first 25 people and the additional people.
- So the total function becomes:
[tex]\[ f(n) = 525 + 14 \times (n - 25) \][/tex]

5. Simplify the function:
- Simplifying [tex]\( f(n) = 525 + 14 \times (n - 25) \)[/tex]:
[tex]\[
f(n) = 525 + 14n - 350 = 14n + 175
\][/tex]

Therefore, the function [tex]\( f(n) = 14n + 175 \)[/tex] describes the total charge, in dollars, for a tour group with [tex]\( n \)[/tex] people, where [tex]\( n \geq 25 \)[/tex].

The correct answer is option A: [tex]\( f(n) = 14n + 175 \)[/tex].