Question

Joe purchased a prepaid phone card for $35.00. Calls cost 9 cents a minute using this card. The credit, C (in dollars), left on the card after it is used for x

minutes of calls is given by the following function.
C(x)=35.00-0.09.x
How much credit is left on the card after Joe uses it for 30 minutes of calls?

Answer 1

• $32.30 is left on the card

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To find the remaining credit plug in the value of x = 30 into equation and calculate:

• C(30) = 35.00 - 0.09*30 = 35.00 - 2.70 = 32.30