What equation do you use to solve this:

Question

you have 3 different prices for coffee .95 (10oz), 1.15 (14oz) and 1.50 (20oz); how many of each price equates to $32.35 (394oz)

Answer 1

10x+14y+20z=394       The total volume of coffee bought.

5x+7y+10z=197

0.95x+1.15y+1.50z=32.35.          The total  cost of the coffee bought.

19x+23y+30z =647

The third equation is missing.

Check your question: sth in reference to the total number of cups of coffee bought.

 

You may then use Cramer's Rule, use your calculator (enter the values into your matrix)

 

The third way is algebraically. Eliminate a variable,

for instance, 

 

Multiply by (-3)(5x+7y+10z=197)

-15x -21y -30z=-591

19x+23y+30z =647

 

Add these two eqns.

 

4x+ 2y = 56

2x + y = 28

Remember, you will need one more information to solve either way.