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-   -   Why did we bring two unknown values x and y? (http://mymathforum.com/elementary-math/344184-why-did-we-bring-two-unknown-values-x-y.html)

Ganesh Ujwal May 3rd, 2018 01:35 AM

Why did we bring two unknown values x and y?
 
Wealth tax percentages with remaining taxes like Income tax etc.

2013 - 1.4% + income tax...

2014 . 1.8% + income tax...

If the wealth tax collected in 2013 was 80% of that collected in 2014, the total wealth tax collected in 2013 was approximately what percentage more than that collected in 2014?

Solution: Wealth tax = 2013 = (80/100) 2014

2013/2014 = 4/5

2013 - wealth tax - 1.4%

2014 - wealth tax - 1.8%

(1.4x/1.8y) = (4/5)

x/y = 4/5 x 9/7 = 36/35

Percentage more than = 1/35 x 100 = 2.85%

Why did we bring two unknown values x and y?

mrtwhs May 3rd, 2018 03:40 AM

Suppose that today you give me 10%. Now suppose that tomorrow I give you 10%. Are we even?

skipjack May 3rd, 2018 05:01 AM

Quote:

Originally Posted by Ganesh Ujwal (Post 593735)
Why did we bring two unknown values x and y?

Your description was inaccurate (the second occurrence of "wealth tax collected" should have been "wealth taxed").

Let the amount taxed (as distinct from the amount of tax) be x for 2013 and y for 2014 (separate letters for the separate years).

The wealth tax collected is then 1.4% of x for 2013, and 1.8% of y for 2014.

You are told that 1.4% of x was 80% of 1.8% of y, so 0.014x/(0.018y) = 80% = 4/5,
which implies that x/y = 4/5 * 1.8/1.4 = 36/35.

Ganesh Ujwal May 3rd, 2018 07:32 AM

Quote:

Originally Posted by mrtwhs (Post 593740)
Suppose that today you give me 10%. Now suppose that tomorrow I give you 10%. Are we even?

Yes! but how is your question related to my doubt?

mrtwhs May 4th, 2018 03:57 AM

Quote:

Originally Posted by Ganesh Ujwal (Post 593753)
Yes! but how is your question related to my doubt?

It answers your doubt if you bother to "think". Without the x and y, the 1.4% and 1.8% are meaningless. You must have 1.4% of something. Without any other information you can say 1.4% of x. Now it has meaning.

Going back to my example ... you give me 10% today and I give you 10% tomorrow. Are we even? The answer is "it depends". If today you give me 10% of $100 and tomorrow I give you 10% of a half eaten banana, then I don't think you would consider that an even exchange.


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