Question 890097
Any question of this type can be understood and handled in the general manner shown here:  <a href="http://www.algebra.com/tutors/mixture-price-two-part-both-parts-unknown.lesson?content_action=show_dev">Mixture: Two-Part, price or cost, both material amounts unknown - http://www.algebra.com/tutors/mixture-price-two-part-both-parts-unknown.lesson?content_action=show_dev</a>


If put the actual given numbers into the equations, you would use
{{{(4u+10v)/18=6}}} and {{{u+v=18}}}.
u = how much of the lower cost candy
v = how much of the higher cost candy


The rational equation can be simplified before using:
{{{(2u+5v)/18=3}}}
{{{highlight_green(2u+5v=54)}}}