Question 163953
total messages for the month is 3850 as follows:
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let C = cost
let M = number of messages greater than 1000
formula is:
C = $10 + $.01*M
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substitute known values in equation.
$38.50 = $10 + $.01*M
subtract $10 from both sides of equation.
$28.5 = $.01*M
divide both sides of the equation by $.01.
2850 = M
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looks like number of messages greater than 1000 is 2850.
to prove, substitute in original equation.
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$38.50 = $10.00 + $.01*2850
$38.50 = $10.00 + $28.50
$38.50 = $38.50
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the value of 2850 for M is good.
total messages for the month would be 2850 + 1000 = 3850.
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