Question

The school's lemonade is $10\%$ lemon juice by volume, and the rest is sugar water. How many liters of lemon juice must be added to 20 liters of sugar water to make the school's lemonade?

Answer 1

20/9

Explanation:

AOPS

Answer 2

20/9

10 % = lemon juice, so 90 % = sugar water.
Therefore, we have a ratio of lemon juice to sugar water:
10:90, or 1:9

1/9 times 20 liters of sugar water = 20/9
:)