Question

12 litres of a solution contains 331 % of acid.
3.
How many litres of water is to be added to
reduce the acid percentage to 20%​

Answer 1

CORRECT QUESTION:

Q: 12 litres of a solution contains 33⅓ % of acid. How many litres of water is to be added to reduce the acid percentage to 20%?

Answer:

• The amount of water added = 8 litres

Step-by-step explanation:

Given that:

• Total amount of solution = 12 litres
• Percentage of acid in solution = 33⅓ % = 100/3 %

Let us assume:

• x litres of water is to be added to reduce the acid percentage to 20%.

To Find:

• Amount of water added.

Now we have,

• Amount of solution after adding water = (12 + x) litres
• Percentage of acid in solution = 20%

But, In both cases amount of acid is same.

Finding the amount of water added:

• According to the question.

→ (12 + x) × 20% = 12 × 100/3 %

• Both side percent cancelled.

→ (12 + x) × 20 = 12 × 100/3

→ 240 + 20x = 1200/3

→ 240 + 20x = 400

→ 20x = 400 - 240

→ 20x = 160

→ x = 160/20

→ x = 8

∴ The amount of water added = 8 litres

Answer 2

Given

• Amount of the solution = 12 L
• Percent of the acid in the solution = 33 ⅓ %

To find

• Amount of water which is added

Solution

• Amount of solution after water is been added = (12 + x) L
• The percentage of acid present in solution = 20 %

Now, according to the question :-

• (12 + x) × 20% = 12 × 100/3 %
• (12 + x) × 20 = 12 × 100/3
• 240 + 20x = 400
• 20x = 400 - 240
• 20x = 160
• x = 160/20
• x = 8

Hence, the amount of water added is 8 L