Question 1137351
<pre>
The two equations for the given conditions are:
 n +  m = 20    (1)
2n + 4m = 64    (2)

(2) -->  n + 2m = 32

Subtract (1) from this to get m:
  n + 2m  = 32
- n  - m  = -20
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  (you do the rest here)

 then plug in that value into (1) or (2) and solve for n.  


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