Question

A 70 L mixture of juice and water contains 10% of water. How much water must be added to make the water content 12.5% of the resulting mixture?

• A. 1 L
• B. 3 L
• C. 2 L
• D. 4 L

Answer 1

The correct option is C

2 L

Let the required quantity of water = $x$ L

According to the question,
$70\times \frac{10}{100}+x=(70+x)\times \frac{12.5}{100}$

$\Rightarrow 7+x=(70+x)\times 0.125$
$\Rightarrow 7+x=8.75+0.125x$
$\Rightarrow x-0.125x=8.75-7$
$\Rightarrow 0.875x=1.75$
$\Rightarrow x=2$

2 L of water must be added to make the mixture contain 12.5% of water.