Question 1042370
You need a 10% alcohol solution. On hand, you have a 50 mL of a 30% alcohol mixture.
 How much pure water will you need to add to obtain the desired solution?
A) Write an equation using the information as it is given above that can be used to solve this problem. Use x as your variable to represent the amount of pure water you need to use.
:
The mixture you have is 30% alcohol, therefore it is 70% water. (total is 100%)
Result is to be 10% alcohol, therefore it is 90% water
:
the equation using the decimal form of percent, based on the amt of water
.70(50) + x = .90(x+50)
35 + x = .90x + 45
x - .9x = 45 - 35
.10x = 10
x = 10/.1
x = 100 ml of pure water required