Question 436908
Let {{{p}}} = gallons of 5% yellow paint needed
given:
{{{ p + .4 }}} = gallons of final mixture
{{{ .02*.4 = .008 }}} gallons of 2% yellow
{{{ .05p }}} = gallons of 5% yellow needed
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{{{ (.05p + .008)/(p + .4) = .04 }}}
{{{ .05p + .008 = .04*(p + .4) }}}
{{{ .05p + .008 = .04p + .016 }}}
{{{ .01p = .008 }}}
{{{ p = .8 }}}
.8 gallons of the 5% yellow pigment paint should be used
check:
{{{ (.05*.8 + .008)/(.8 + .4) = .04 }}}
{{{ .048 / 1.2 = .04 }}}
{{{ .048 = .048 }}}
OK