<PRE><B>Question 1115493</B>
12 cans of condensed milk and how many jars of instant coffee?
====================================================================
6 cups of coffee and 7 cups of tea $5.90
18 cups of coffee and 5 cup of tea $9.70
find 7 cups of coffee and 6 cups of tea
:
6x + 7y = 5.90 multiply all times 3:
18x + 21y = 17.70 (1)
18x + 5y = 9.70 subtract this equation from (1):
-----------------------------------------------
18x + 21y = 17.70
-
18x + 5y = 9.70
----------------
0x + 16y = 8
16y = 8
y = 0.50 tea is 0.50 per cup
6x + 7y = 5.90
6x + 7(0.50) = 5.90
6x + 3.50 = 5.90
6x = 2.40
x = 0.40 coffee is 0.40 per cup
Now you find the cost of 7 cups of coffee and 6 cups of tea. Use your calculator.
The process is the same for all 3 problems, follow my work to solve the other two.
Happy learning,
John

</PRE>