when making a long distance call from a cetain pay phone, the first three minutes of a call cost $2.25. After that, each additional minute or portion of a minute of that call costs $0.30. Using the inequality C is greater than or equal to 2.25+0.30(X-3)where C is the total cost and X is the number of minutes, find the number of minutes one can call long distance for $4.35. Please show the work so i can do it.

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anonymous · Answer

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anonymous · Answer

^^please help me on this assignment. Please show the work so i can know how to do it. Thanks

anonymous · Answer

well you already have the equation:
C=2.25+0.30(X-3).. that means you can get the cost for known number of minutes and vice versa

anonymous · Answer

so just substitute for C=4.35 (the cost) to get the number of minutes, that's:
4.35=2.25+0.30(X-3).. just solve the equation for X.

anonymous · Answer

$$4.35=2.25+0.30(X-3) \implies 0.30(X-3)=4.35-2.25$$
$$\implies 0.30(X-3)=2.1 \implies X-3=7 \implies X=10$$

anonymous · Answer

10 minutes is the answer you're looking for :)

anonymous · Answer

does that make sense to you?