A fitness center charges $3 per visit plus a monthly fee of $30. How much would it cost in one month if Ella has 18 visits?

Multiply the 18 visits by $3 per visit: 18 × $3 = $54. Then add the monthly fee of $30: $54 + $30 = $84. The total cost is $84, choice C.

AI-written and checked against the verified answer.