Question

You need a 45% alcohol solution. On hand, you have a 350 mL of a 15% alcohol mixture. You also have 70% alcohol mixture. How much of the 70% mixture will you need to add to obtain the desired solution?
You will need
_____ mL of the 70% solution

Answer 1

Answer:

420

Step-by-step explanation:

Amount in the 45% solution + amount in the 70% solution = amount in the 45% solution

0.15 × 350 + 0.70 × V = 0.45 × (350 + V)

52.5 + 0.70V = 157.5 + 0.45V

0.25V = 105

V = 420

You need 420 mL of the 70% solution.