Question 725957
x+y=16
5x+4y<=100
 we need only 16 total maximum 
5*16=80 
4*16=64
so the cost could range from 64 to 80 dollars
so she could have from 0 to 16 teddy bears and 0 to 16 gift cards
x  y
16 0
15 1
14 2
13 3
12 4
etc

or
x y
0 16
1 15
2 14 
etc