In this case, we'll have to carry out several steps to find the solution.
Step 01:
Data:
hazelnuts = $7.50 / lb
peanuts nuts = $4.60 / lb
total mixture (mass) = 34 lb
total mixture (price) = $6.39 / lb
Step 02:
system of equations:
x = pounds of hazelnuts
y = pounds of peanuts
x + y = 34 eq.1
7.50x + 4.60y = 6.39*34 eq.2
x, eq.1:
x = 34 - y
x in eq.2:
7.50(34 - y) + 4.60y = 6.39*34
255 - 7.5y + 4.6y = 217.26
-7.5 y + 4.6y = 217.26 - 255
-2.9y = -37.74
y = (-37.74) / (-2.9)
y = 13.01
y, eq.1 :
x + 13.01 = 34
x = 34 - 13.01 = 20.99
The answer is:
x = 21 pounds of hazelnuts
y = 13 pounds of peanuts