Question 169162
The Smith family pays $60 for 4 adult meals and 1 kid's meal.
The Jones family pays $42 for 2 adult meals and 2 kid's meals.
How much was each adult meal and each kid's meal.
Here is what I have so far . . .
4x + y = 60
2x + 2y = 42
:
These are the right equations, but you want to multiply one or both equations,
 so that you can eliminate one of the variables.
:
In this case if we multiply the 1st equation by 2 and subtract we eliminate y
8x + 2y = 120
2x + 2y = 42
--------------- subtraction eliminates y, find x
6x + 0 = 78
x = {{{78/6}}}
x = $13 for adult meal
:
Use the 1s equation to find y, substitute 13 for x:
4(13) + y = 60
52 + y = 60
y = 60 - 52
y = $8 for kids meal
;
;
Check solution in the 2nd equation
2(13) + 2(8) = 42
26 + 16 = 42, confirms our solutions