word problem to equation question  TOPIC_SOLVED

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word problem to equation question

Postby Howdy on Mon Feb 15, 2010 3:08 pm

Hello, I an confused about what the starting equation should be for this simple word problem:
The net price of a calculator is $54 after a 10% discount is applied.
What is the list price?

It seems that I should start out with this: (where x = list_price)

x - ( x(.10) ) = 54

...but I can't figure out where to go from there.
I know I can instead start out with this:

x(.90)  =  54          check:  60 - ( 60(.10) ) = 54
/.90 /.90 60 - 6 = 54
x = 60
check: 60(.90) = 54

But that seems like a jump and that I should be trying to work from the first one to the second. What should I do?
(this is out of an old book , I have no instructor.)
Thank you.
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Postby stapel_eliz on Mon Feb 15, 2010 3:50 pm

I'm not sure what you mean by a "jump" in going from 1x - 0.1x to 0.9x...? :confused:
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Re: word problem to equation question  TOPIC_SOLVED

Postby Howdy on Mon Feb 15, 2010 5:26 pm

I see! I was confusing myself with the way I was stating it.

x - ( x(.10) ) = 54   <-- original

x - .10x = 54 <-- stated as it should be
1x - .1x = 54 <-- As you showed me, with the coefficient in the right place.
.9x = 54 Also important for me is the assumed coefficient 1 in x
/.9 /.9 Then the (1 - .1) becomes clear
x = 60


Thank you ,
I knew I was missing something. Now I can move on without it nagging at me.
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