Question 1007859
Let 44 cent stamps be x
Let 20 cent stamps be y

x + y = 40
.44x + .20y = 13.28
Multiply second equation by 5 to eliminate y:
x + y = 40
2.2x + y = 66.4
Subtract:
-1.2x = -26.4
x = 22
Substitute x into original equation to get y:
x + y = 40
22 + y = 40
y = 18

Final Answer:
44 cent stamps = 22
20 cent stamps = 18