Question 198759
Let {{{w}}}= cups of water he uses
{{{30 - w}}}= cups of lemon juice he uses
given:
{{{w/(30-w) = 4/1}}}
Multiply both sides by {{{30 - w}}}
{{{w = 4*(30 - w)}}}
{{{w = 120 - 4w}}}
{{{5w = 120}}}
{{{w = 24}}}
{{{30 - w = 6}}}
Roger needs 24 cups of water and 6 cups of lemon juice