Question

You need a 35% alcohol solution. On hand, you have a 715 mL of a 20% alcohol mixture. You also have 90% alcohol mixture. How much of the 90% mixture will you need to add to obtain the desired solution?

Answer 1

you will need 90% to obtain the desired 75%

Answer 2

90% Solution

Explanation:

5% of 90 + 90% of x = 75% of (90 + x)

5×90/100 + 90x/100 = 75×90/100 + 75x/100

Or 90x/100 - 75x/100 = 75×90/100 - 5×90/100

Or 15x/100 = 90×70/100

Or X = 420ml

You Will Need ML Of The 90% Solution To Obtain ML Of The Desired 75% Solution.