Question 1150072
A paint that is contains 21% green dye is mixed with another that is 15% green dye. If you need 60
gallons of 19% green dye, how much of each should you use? Hint: the problem only tells you one variable
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t = 21%
f = 15%
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t + f = 60
21t + 15f = 19*60
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Hint:  we don't need hints.
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If you meant to ask to have it done with only 1 variable, "Hint: the problem only tells you one variable" is not a request to do that.
The problem doesn't tell us any variables.