A health club charges non-members 5 dollars per day to swim and 9 dollars per day for an exercise class. Members pay a yearly fee of 300 dollars plus 4 dollars per day to attend an exercise class and no swim fee. If Robert swims and takes an exercise class every time he goes to the gym, which equation shows the number of days, d , he must use the gym to make the membership worthwhile?
Answer
A
5 d plus 9 d is equal to 300 plus 4 d
B
the fraction with numerator 5 d plus 9 d and denominator 300 is equal to 4 d
C
the fraction with numerator 5 d plus 9 d and denominator 4 d is equal to 300
D
5 d plus 9 d is equal to 300 minus 4 d
Explanation
As a non-member, Robert pays $5 for swimming and $9 for the exercise class each day, or 5d + 9d dollars for d days. As a member, he pays the $300 yearly fee plus $4 per day for the class, or 300 + 4d dollars. The membership becomes worthwhile when these costs are equal, so the equation is 5d + 9d = 300 + 4d, choice C.
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