Question 422738
Write a cost equation for each statement:
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Let m = no. of minutes used (greater than 100 min)
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One plan is $20 with 30 minutes free and .10 for each additional minute.
C = .10(m-30) + 20
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The second plan is $51 with 100 minutes free and .o4 for each additional minute.
C = .04(m-100) + 51
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Then how can I compare the costs?
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How many minutes will you have to use to make the 1st plan more expensive than the 2nd plan?
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 1st plan cost more than 2nd plan
 .10(m-30) + 20 > .04(m-100) + 51
 .10m - 3 + 20 > .04m - 4 + 51
 .10m + 17 > .04m + 47
 .10m - .04m > 47 - 17
.06m > 30
m > {{{30/.06}}}
m > 500 minutes use, will make the 2nd plan a better deal
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Check this for yourself, assume m = 501 min
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did this make sense to you?