Kelly's company is painting a building a unique shade of purple. She needs 12 pints of red paint for every 8 pints of blue paint. Using that ratio, if she uses 65 pints of paint how much blue paint is needed?

1 Answer
Teun · Stefan V.
Dec 13, 2016

#65 * (8 / [12 + 8]) = 26#

#26# pints of blue paint are needed.

Explanation:

#65# is the total amount of paint used. The ratio of blue to red is #8:12#. The ratio can be simplified to #2# pints of blue for every #3# pints of red. So #2/5# pints are blue, #3/5# pints are red.

Multiply the fraction of pints of blue by the total number of pints.

#65 * (2/5) = 26#

#26# being the number of pints of blue paint.

For red paint, you would do

#65 * (3/5) = 39#

To check if we are correct,

#26 + 39 = 65#

#26:39 -> 26/13 : 39/13 -> 2:3#

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