How many milliliters of a 12% alcohol solution and how many milliliters of a 30% alcohol solution must be mixed to obtain 72 ml of a 20% alcohol solution?

Target concentration = 20%.

Ratio of 12% and 30% alcohols needed

30-20 : 20-12 = 10:8 = 5:4

Volume of 12% = 72 mL * (5/(5+4)) = 40 mL

Volume of 30% = 72 mL *(4/(5+4)) = 32 mL

Total = 40+32 = 72 mL of 20%

step-by-step explanation:

there is a formula i can give you:

it is r^2*n*sin(360/n) divided by 2 where r represents the "radius" and n is the number of sides.

plug them in:

(10sqrt(3))^2*6*sin(360/6) divided by 2

100*3*6*sin(60) divided by 2

900*sin(60)

900*sqrt(3)/2

450*sqrt(3)

approx is 779.4 cm^2

a

step-by-step explanation:

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