Question 945690
Let {{{ x }}} = gallons of 5% acid solution needed
{{{ .05x }}} = gallons of acid in 5% acid solution
{{{ .1*20 = 2 }}} = gallons of acid in 10% acid solution
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{{{ ( .05x + 2 ) / ( x + 20 ) = .08 }}}
{{{ .05x + 2 = .08*( x + 20 ) }}}
{{{ .05x + 2 = .08x + 1.6 }}}
{{{ .03x = .4 }}}
{{{ x = 13.333 }}}
13.333 gallons of 5% acid solution are needed
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check:
{{{ ( .05x + 2 ) / ( x + 20 ) = .08 }}}
{{{ ( .05*13.333 + 2 ) / ( 13.333 + 20 ) = .08 }}}
{{{ 2.667 / 33.333 = .08 }}}
{{{ 2.667 = .08*33.333 }}}
{{{ 2.667 = 2.667 }}}
OK