What is the value of x in the equation .4 = [20%]/[x]?

  • Thread starter Tarnix
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    Algebra
So you're right, that's a solution. But I think the idea was to get a more general form. So you should multiply by 5 and divide by 2 to get x=\frac{5}{2}, which is the general solution.In summary, the conversation discussed how to solve the equation .4 = [20%]/[x] by converting decimals to fractions and substituting them into the equation. The final solution was found to be x = 1/2 or x = 5/2.
  • #1
Tarnix
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0

Homework Statement



.4 = [20%]/[x]


Homework Equations





The Attempt at a Solution



This is what I tried...but I know this isn't right as I need an actual value for x.

.4 = (.2)(x^-1)
.4 / .2 = x^-1
2 = x^-1
2 = 1 / x
 
Last edited:
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  • #2
You're almost done. multiply both sides by x, then divide by 2.
 
  • #3
2(x) = (1/x)(x)
2x = 1
x = 1/2

Is that right?
 
  • #4
aye.
 
  • #5
[tex].4=\frac{.2}{x}[/tex]

Converting decimals to fractions ...

[tex].4=\frac{4}{10}=\frac 2 5[/tex]

[tex].2=\frac{2}{10}=\frac 1 5[/tex]

Substituting ...

[tex]\frac 2 5 = \frac{1}{5x}[/tex]
 
  • #6
I don't think that is correct. If I solved Roco's equation I would get:
2/5 = 1/5x
(2/5) / (1/5) = x
2 = x

When really the solution is .5

I think you mean by substituting fractions would be...
2/5 = (1/5) / x

But thank you for trying to help :D I just don't want someone else to get confused if they look at this later.
 
  • #7
Tarnix said:
I don't think that is correct. If I solved Roco's equation I would get:
2/5 = 1/5x
(2/5) / (1/5) = x
No you wouldn't, you'd get [tex]\frac{2/5}{1/5}=\frac{1}{x} \Rightarrow x=\frac{1}{2}[/tex]
 

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