SOLUTION: A printer has ink that is 7% cobalt blue color and ink that is 23% cobalt blue color. How many ounces of each ink are needed to make 1 gallon (128 ounces) of ink that is 15% cobalt

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Question 896214: A printer has ink that is 7% cobalt blue color and ink that is 23% cobalt blue color. How many ounces of each ink are needed to make 1 gallon (128 ounces) of ink that is 15% cobalt blue color?

Found 2 solutions by josgarithmetic, richwmiller:
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
L=7
H=23
T=15
M=128 but you must understand this is NOT OUNCES. Why? It is something else.
u = unknown amount of 7%
v = unknown amount of 23%

A unit conversion may be needed; but if you are justified in ignoring it,

%28Lu%2BHv%29%2FM=T and u%2Bv=128

A lesson for this in general is here: Mixing two concentrations for known amount of mixture - http://www.algebra.com/my/Mixtures%3A-All-in-Symbols.lesson?content_action=show_dev

Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
a+b=128,
.07a+.23*b=.15*128
a=64, b=64
Equal amounts of 7% and 23%
check
.07*64+.23*64=.15*128
4.48+14.72=19.20
19.20=19.20
ok