Answer:
The cost of a birthday card is $2.2
Explanation:
Let 
x-----> represents the cost of a birthday card 
y ----> represents the cost of a thank-you note
we know that 
 Package A 
 3x+2y=9.60 
2y=9.60-3x 
Multiply by 3 both sides 
3(2y)=3(9.60-3x) 
6y=28.80-9x -----> equation A 
 Package B 
 8x+6y=26.60 -----> equation B 
 Solve the system by substitution 
Substitute equation A in equation B and solve for x 
8x+(28.80-9x)=26.60 
9x-8x=28.80-26.60 
x=2.2 
Find the value of y (equation A) 
6y=28.80-9x 
substitute the value of x and solve for y 
6y=28.80-9(2.2) 
6y=9 
y=1.5 
The solution is the point (2.2,1.5) 
therefore 
The cost of a birthday card is $2.2