Question 412657
{{{(.6*9 + .9a)/(9 + a) = .85}}}
{{{ 5.4 + .9a = .85*(9 + a)}}}
{{{ 5.4 + .9a = 7.65 + .85a}}}
{{{ .05a = 2.25}}}
{{{a = 45}}} gallons
check answer:
{{{(.6*9 + .9*45)/(9 + 45) = .85}}}
{{{( 5.4 + 40.5)/54 = .85}}}
{{{ 45.9/54 = .85}}}
{{{45.9 = 45.9}}}
OK