Question 998946
You can learn to make sense of any and all two-part mixture problems which fit this form using this lesson, designed for this purpose:


<a href="http://www.algebra.com/my/mixture-price-two-part-both-parts-unknown.lesson?content_action=show_dev">LESSON: http://www.algebra.com/my/mixture-price-two-part-both-parts-unknown.lesson?content_action=show_dev</a>


The exercise question solution can also be setup using just a single variable.  To start yours this way, 
Let x be the quantity of the lower priced tea and therefore
100-x will be the quantity of the higher priced tea.


Setup this equation:
{{{(2x+4(100-x))/100=2.5}}}