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Two communications companies offer calling plans. With Company X, it costs 30¢ to connect and then

3¢ for each minute. With Company Y, it costs 15¢ to connect and then 2c for each minute. Write and
simplify an expression that represents how much more Company X charges, in cents, for n minutes.

User Jhibberd
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1 Answer

7 votes

Answer: n+15

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Step-by-step explanation:

  • n = number of minutes
  • cost of company X = 3n+30
  • cost of company Y = 2n+15

To find out how much more company X charges, we subtract the two cost expressions

CompanyX - CompanyY = (3n+30)-(2n+15) = 3n+30-2n-15 = n+15 which is the final answer.

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An example:

Let's say you talk on the phone for n = 20 minutes.

Company X would charge you 3n+30 = 3*20+30 = 90 cents

Company Y would charge you 2n+15 = 2*20+15 = 55 cents

The difference of which is 90-55 = 35 cents.

If you plugged n = 20 into the n+15 expression we got, then n+15 = 20+15 = 35 matches up with the previous 35 cents.

This example helps confirm the answer. I'll let you try out other examples.

User Mzzzzb
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