<PRE><B>Question 182641</B>
Let {{{a}}}= ounces of 49 cent apple juice needed per 8 ounce can
Let {{{b}}}= ounces of 25 cent apple drink needed per 8 ounce can
given:
(1) {{{a + b = 8}}}
The cost per ounce of apple juice is:
{{{49/8 = 6.125}}} cents/oz
The cost per ounce of apple drink is:
{{{25/8 = 3.125}}} cents/oz
-------------------------------------
(2) {{{6.125a + 3.125b = 39}}}cents
Multiply both sides of (1) by {{{3.125}}}
(1) {{{a + b = 8}}}
(1) {{{3.125a + 3.125b = 25}}}
Subtract (1) from (2)
(2) {{{6.125a + 3.125b = 39}}}
(1) {{{-3.125a - 3.125b = -25}}}
(3) {{{3a = 14}}}
(3) {{{a = 4.67}}} oz
and, since
(1) {{{a + b = 8}}}
{{{b = 8 - 4.67}}}
{{{b = 3.33}}} oz
4 2/3 oz of juice and 3 1/3 oz of drink per 8 oz can are needed
check:
(2) {{{6.125a + 3.125b = 39}}}
(2) {{{6.125*4.67 + 3.125*3.33 = 39}}}
(2) {{{28.583 + 10.416 = 39}}}
{{{38.998 = 39}}} close enough</PRE>