Question 96682
A certain creme mixture contains 12 grams of creme A, 18.6 grams of petrolatum, and 30 grams univase. The pharmacist needs to make a 480-gram mixture containing the same ratio of ingredients. How much of each ingredient should she 
include?
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Here is one way to do it, by proportions
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Let the amt of the three ingredients be x, y, and z
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Find the original total amt:  12 + 18.6 + 30 = 60.6
:
Find x
{{{12/60.6}}} = {{{x/480}}}
Cross mult:
60.6x = 12 * 480
60.6x = 5760
x = {{{5760/60.6}}}
x = 95.05
:
Find y:
{{{18.6/60.6}}} = {{{y/480}}}
60.6y = 18.6 * 480
60.6y = 8928
y = {{{8928/60.6}}}
y = 147.3 
:
Find z
{{{30/60.6}}} = {{{z/480}}}
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you should be able to complete this problem
:
you can check the amts by adding them all up and seeing if they ~ 480