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?

The percentage of lemon in the juice is 10%
The percentage of water sugar is (100-10)=90%
The quantity of lemon in 20 liters of sugar water will be:
amount=(percentage of lemon)/(percentage of sugar water)×(amount of sugar water)
=10/90×20
=2 2/9 liters 

The correct awnser is 29.76 pounds.

-2x + 7 = 7

subtract 7 from both sides.

-2x = 0

divide both sides by -2.

x = 0

the value of x is equal to 0.