How many litres of a 84% of concentrated acid needs to be mixed with a 78%…
2024
How many litres of a 84% of concentrated acid needs to be mixed with a 78% solution of concentrated acid to get a 24 litres solution of 80% concentrated acid ?
- A.
1
- B.
7
- C.
9
- D.
8
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Correct answer: D
Answer: 8 litres.
Let x be the litres of 84% solution and y be the litres of 78% solution.
Write the equation for total acid: 84x + 78y = 80(x + y).
Simplify the equation: 84x + 78y = 80x + 80y ⇒ 4x = 2y ⇒ x:y = 1:2.
Total parts = 1 + 2 = 3. So x = (1/3) × 24 = 8 litres.
Therefore, 8 litres of the 84% solution are needed.