Question 495789
Let {{{x}}} = gallons of pure acid to be added
given:
{{{ .5*4 = 2 }}} gallons of acid in 50% solution
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{{{ (x + 2) / ( x + 4 ) = .6 }}}
{{{ x + 2 = .6*( x + 4 ) }}}
{{{ x + 2 = .6x + 2.4 }}}
{{{ .4x = .4 }}}
{{{ x = 1 }}}
1 gallon of pure acid needs to be added
check:
{{{ (x + 2) / ( x + 4 ) = .6 }}}
{{{ (1 + 2) / ( 1 + 4 ) = .6 }}}
{{{ 3/5 = .6 }}}
{{{ 3 = 3 }}}
OK