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Missing something from the equation...WHAT IS IT?

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Missing something from the equation...WHAT IS IT?

by smclean23 » Sun Jul 06, 2008 4:13 pm
After paying a 10 percent tax on all income over $3,000, a person had a net income of $12,000. What was the income before taxes?
(A) $13,300
(B) $13,000
(C) $12,900
(D) $10,000
(E) $9,000

I backsolved and got the answer but I want to use a more structured way of getting the answer.

I tried .10(x-3000)=12000, but it seems like I'm missing something from this equation. What is it?
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by dbart06 » Sun Jul 06, 2008 4:24 pm
smclean23,

I too got lost in the formula. I discovered that the formula should read:

x-.1(x-3000)=12000

you set up the equation to find the income that was taxed but you have to subtract that number from x.

hope it helps.
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by smclean23 » Sun Jul 06, 2008 4:27 pm
thanks...makes more sense now...
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by smclean23 » Sun Jul 06, 2008 4:33 pm
Actually, I tried the formula and it doesnt give me 13,000......Do you?
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by dbart06 » Sun Jul 06, 2008 6:18 pm
x-.1(x-300)=12000
you have -.1 times x and -.1 times -300, this make 300 a positive # and then you subtract that from both sides..it gives an equation:

x-.1x=11700 => .9x=11700

x=13000
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by dbart06 » Sun Jul 06, 2008 6:39 pm
x-.1(x-300)=12000
you have -.1 times x and -.1 times -300, this make 300 a positive # and then you subtract that from both sides..it gives an equation:

x-.1x=11700 => .9x=11700

x=13000
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by beeparoo » Wed Jul 09, 2008 10:17 am
dbart06 wrote:x-.1(x-300)=12000
you have -.1 times x and -.1 times -300, this make 300 a positive # and then you subtract that from both sides..it gives an equation:

x-.1x=11700 => .9x=11700

x=13000
But your equation has a minor error: You subtracted 300 when you were supposed to subtract 3000. This will change your answer...
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by dbart06 » Wed Jul 09, 2008 10:35 am
sorry for the typo should be:

x-.1(x-3000)=12000

thanks beeparoo. these are the mistakes that cost me on the test.
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by dbart06 » Wed Jul 09, 2008 10:45 am
sorry for the typo should be:

x-.1(x-3000)=12000

thanks beeparoo. these are the mistakes that cost me on the test.
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by lion147 » Wed Jul 09, 2008 5:46 pm
I think an easier equation is:

3000+0.9x = 12000

Where x is the taxable income, the answer is 3000+x.

i.e. 0.9x = 9000, x = 9000/0.9, x = 10000, answer is 10000+3000.
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by senthil » Wed Jul 09, 2008 6:03 pm
I tried the same way as lioner has done , that is the easiest approach too
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