Question

Please help! A scientist mixed a 26% saline solution with 40mL of 50% saline solution to make a 42% saline solution. How much 26% saline solution should the scientist do?

Answer 1

• 20 ml

Explanation:

x ml of 26% saline solution mixed with 40 ml of 50% saline solution to obtain a 42% saline solution.

The amount of salt is same at the input and output:

• 0.26x + 0.5*40 = 0.42*(40 + x)
• 0.26x + 20 = 16.8 + 0.42x
• 0.42x - 0.26x = 20 - 16.8
• 0.16x = 3.2
• x = 3.2/0.16
• x = 20