Provided that I have copied down your math problem correctly, we have:
p + n = 80
p + 3.09 n = 201.86
Solving the first equation for p: p = 80-n.
Subst. 80-n for p in the 2nd equation: (80-n) + 3.09n = 201.86
Simplifying the left side: 2.09n + 80 = 201.86
Combining the constants, 2.09n = 121.86
Finally, dividing by 2.09: n = 121.86/2.09 = 58.31 pounds of nuts.
This does not match any of the answer choices.
Please check my interpretation of the problem; if my assumptions are wrong, type in the equations yourself for greater clarity.