Write it out as a set of equation:
Let x be number of 8 cent stamps, y be 10 cent stamps, and z be 2 cent stamps.
x=y
z=x+y
8x+10y+2z=440
Lets first solve for x:
from x=y and z=2x(from first equation) the last equation is 
8x+10x+4x=440
22x=440
x=20
know that x=20, you also know that y=20 as well, since z=x+y, z=40.
So 20 8-cent stamps, 20 10-cent stamps, and 40 2-cent stamps.
        
                    
             
        
        
        
Answer:
For every 4 grams there are 3 cashews. 
12g=9. So that means there are 18 cashews in 24 grams. And like we said, there are 3 cashews in every 4 grams. So there are 21 cashews for 161 cals, equating to 28g.
 
        
             
        
        
        
The one that passes through the origin. That one in the lower left part.