SOLUTION: You need a 70% alcohol solution. On hand, you have a 30 mL of a 30% alcohol mixture. You also have 75% alcohol mixture. How much of the 75% mixture will you need to add to obtain t

Question 1036642: You need a 70% alcohol solution. On hand, you have a 30 mL of a 30% alcohol mixture. You also have 75% alcohol mixture. How much of the 75% mixture will you need to add to obtain the desired solution?
Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
You need a 70% alcohol solution.
On hand, you have a 30 mL of a 30% alcohol mixture.
You also have 75% alcohol mixture.
How much of the 75% mixture will you need to add to obtain the desired solution?
:
let a the amt of 75% solution required
:
A typical mixture equation using decimals
.30(30) + .75a = .70(a+30)
9 + .75a = .70a + 21
.75a - .70a = 21 - 9
.05a = 12
a = 12/.05
a = 240 ml of 75% solution
:
:
Check this
.30(30) + .75(240) =.70(240+30)
9 + 180 = .70(270)
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