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Alan purchased a prepaid phone card for $40.25. Calls cost 9 cents per min using the card. The credit, C (in dollars), left on the card after it is used for x min of calls is given by the following function.C(x)=40.25-0.09xHow much credit is left on the card after 15 min of calls?

Respuesta :

We have the function that models the credit C left on the card:

[tex]C(x)\text{ = 40.25 -0.09x}[/tex]

x is the total of mins of calls.

If Alan calls for 15 mins, we have to find the left on the card.

So x = 15 because is the amount of mins.

Replace and solve:

[tex]C(x)\text{ = 40.25-0.09(15)}[/tex][tex]C(x)\text{ = 40.25-1.35}[/tex][tex]C(x)\text{ = 38.9}[/tex]

So, $38.9 is the amount of credit left on the card.

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