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500: x=200:1

I have never seen an equation set up like this before. What do the colons represent? I'm sure it's a very simple equation and I'm stumped.

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Vivian L. | Microsoft Word/Excel/Outlook, essay composition, math; I LOVE TO TEACHMicrosoft Word/Excel/Outlook, essay comp...
3.0 3.0 (1 lesson ratings) (1)
2
Hi Melissa;
This means...
500 is to x as 200 is to 1
It can be expressed as...
500 in the numerator is to x in the denominator, as 200 in the numerator is to 1 in the denominator...
500/x=200/1
Cross-multiply...
500=200x
2.5=x
OR...
500 in the numerator is to x in the numerator, as 200 in the denominator as 1 is in the denominator...
500/200=x/1
2.5=x
Parviz F. | Mathematics professor at Community CollegesMathematics professor at Community Colle...
4.8 4.8 (4 lesson ratings) (4)
1
Division is equivalent of Fractions, the fraction and division signs are interchangeable, but it is weird to write equations as such.
Arthur D. | Effective Mathematics TutorEffective Mathematics Tutor
5.0 5.0 (7 lesson ratings) (7)
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500:x=200:1 is the same as 500/x=200/1
There are two ways to solve the problem.
You can cross multiply to get 200x=500
                                                      x=500/200
                                                      x=2.5
The other way is to multiply 200 and 1 both by 2.5 because 2.5*200=500 !
Therefore 2.5*1=2.5 and x=2.5 again.

Comments

By the way, colons are used to write ratios. You can use a colon, the fraction bar, or the word "to". For example the ratio 3 to 4 is the same as 3/4 or 3:4.
You can use colons when writing proportions also.
 
In fact the old fashioned way to write this problem is
500 : x :: 200 : 1 with the double colon being read as "as".
500 is to x as 200 is to 1