<PRE><B>Question 178479</B>
Let {{{g}}}= the pounds of granola needed
Let {{{b}}}= the pounds of dried bananas needed
In words:
(cost of granola used) + (cost of bananas used) = total cost
given:
(1) {{{g + b = 40}}}
{{{6g + 4b = 5.8*40}}}
(2) {{{6g + 4b = 232}}} 
-----------------------
Multiply both sides of (1) by {{{4}}} and
subtract from (2)
(2) {{{6g + 4b = 232}}} 
(1) {{{-4g - 4b = -160}}}
 {{{2g = 72}}}
{{{g = 36}}} lb
And, from (1)
{{{36 + b = 40}}}
{{{b = 4}}}lb
36 pounds of granola and 4 pounds of bananas are needed
check:
(2) {{{6g + 4b = 232}}} 
{{{6*36 + 4*4 = 232}}}
{{{216 + 16 = 232}}}
{{{232 = 232}}}
OK  </PRE>