<PRE><B>Question 1141418</B>
[ quantity of B ] / [ quantity of A ] = 4/5
also
[ quantity of B ] / [ quantity of A + B ] = 4/9
so, I can say
{{{ 4/9 = x / 468 }}} ( x will be in ml )
{{{ 4*468 = 9x }}}
{{{ 9x = 1872 }}}
{{{ x = 208 }}}
208 ml of B are needed
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check:
{{{ 4/5 = 208 / ( 468 - 208 ) }}}
{{{ 4/5 = 208 / 260 }}}
{{{ 4*260 = 5*208 }}}
{{{ 1040 = 1040 }}}
OK</PRE>