You can
put this solution on YOUR website!You have the formula in your head
You just can't get it out
Let
= Miriam's monthly bill
Let
= the number of text messages sent in the
month of June by Miriam
= the number of text messages over
Miriam's monthly bill is:
dollars
Her monthly bill is $38.50. I'll show it in terms of cents
cents
Subtract
from both sides
Add
to both sides
messages
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It might help to go over the units involved in the 1st
formula which was
dollars
The
really stands for ($10/1000 messages)x(1000 messages)
And the other term is really (.1 dollars/message)x(t - 1000 messages)
The units work out to dollars for both terms
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You can check the answer
OK
You can
put this solution on YOUR website!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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