Who can help me with math?

[thehstrybean]

OK, I have a problem in a review book that says this:

"The total cost of a retail item including sales tax at a rate of 9.25%."

Define the variables for the input and output, and write the equation.

So, would the input be "x"=total cost, output be "y"=sales tax, so the equation = ?

I think that's entirely wrong...can anyone help? I'm so lost

 

[VTHodge]

x / (1 + y) = retail

EDIT: I'm not sure exactly what it is you are asking. There are three variables "Retail Cost", "Sales Tax" and "Total Cost". You can write a function for any of the three, using any of the other two as "inputs".

 

[thehstrybean]

That's what I thought...

Another one says "The amount remaining on a $30 phone card @ $.05 per minute"

So, would it be y=$30-$.05(x), where y=amount remaining, and x=minutes used?

 

[VTHodge]

Yes, that is correct.

With the % problems, don't forget to convert the percentages to decimal. 9.25% = 0.0925

 

[thehstrybean]

OoO...Almost forgot about that one...

Thanks...