Question 766464
This can be solved using system of equations.

Let buy x lb of cashew and y lb of peanuts.

x + y = 31 .....(1)

Cost of cashew and peanuts will be 

4.4x + 1.2y = 6 ......(1)

Solving these equation will provide the solution.

lets replace y = 31 - x from equation (1) into equation (2)
4.4x + 1.2 (31 - x) = 6 
4.4x + 37.2 - 1.2x = 6
3.2x = 31.2
x = 9.75

substituting the value sin equation (1) will give
y = 31 - 9.75 = 21.25

Cashews weight will be 9.75 lb
peanuts weight will be 21.25 lb