Answer: each soda costs $1.5 and each hotdog costs $3.
Explanation:
If H is the price for one hotdog and S is the price for one soda, we have the equations:
for Jack.
3*H + 2*S = $12
For Angie.
1*H + 4*S = $9
Now we can isolate one of the variables in one of the equations and then replace it in the other equation, let's isolate H in the second equation:
H = $9 - 4*S
now we replace it in the first eq
3*H + 2*S = $12
3*($9 - 4*S) + 2*S = $12
$27 - 12*S + 2*S = $12
-10*S = $12 - $27 = -$15
S = $15/10 = $1.5
Now we can replace it in the equation for H and get:
H = $9 - 4*$1.5 = $3
So each soda costs $1.5 and each hotdog costs $3.