Whatever% of anything is just (whatever/100) * anything.

let's say we'll add "x" cups of pure vinegar, pure vinegar meaning is 100% vinegar.

how much vinegar is there in "x" cups of 100% vinegar? well (100/100) * x, or just "x".

how much vinegar is there in 10 cups of 10% vinegar? well, (10/100) * 10, or just 1.

say after adding the "x" cups to the 10 cups, we end up with "y" cups, of 50% of vinegar.

how much is 50% of y? well, (50/100) * y or 0.5y.

bearing in mind that x+10 = y, both cups amounts added up, and that x+1=0.5y, both vinegar amounts added up, thus

$\bf \begin{array}{lccclll}
&\stackrel{cups}{amount}&\stackrel{vinegar~\%}{amount}&\stackrel{vinegar~cups}{quantity}\\
\textit{100\% vinegar}&x&1.00&x\\
\textit{10\% cups}&10&0.10&1\\
------&------&------&------\\
mixture&y&0.5&0.5y
\end{array}
\\\\\\
\begin{cases}
x+10=\boxed{y}\\
x+1=0.5y\\
----------\\
x+1=0.5\left( \boxed{x+10} \right)
\end{cases}
\\\\\\
x+1=0.5x+5\implies 0.5x=4\implies x=\cfrac{4}{0.5}\implies x=8$

4 0

3 years ago

mrs west is 14 years younger than her aunt. If mrs west's age in years is as much below 60 as her aunts age is over 40 how old i

Natali [406]

So, the age of the aunt is 57 which is 17 years above 40 and the age of west is >>x-14=43 >> 43 which is 17 years below 60

4 0

3 years ago

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