Question

Jack and Jill went to Burger Queen. Jack bought 2 hamburgers and 3 shakes for
$4.21 while Jill bought 3 hamburgers and 2 shakes for $5.24. The cost of 1
hamburger and 1 shake is:
A) $1.03
B) $1.54
C) $1.89
D) $9.45

Answer 1

Write down the facts:

2h+3s = 4.21
3h+2s = 5.24

Now you can solve for h and s, and calculate h+s. Nope, too much work.

Instead, just add the two equations, and you see that

5h+5s = 9.45
So, divide by 5 to get
h+s = 1.89