Main focus is on (sum of cost)/(total pounds)=60 cents per pound.
Let g = how many pounds of the 50 cent per pound nuts.
Fill in the expressions for numerator and denominator in the "Main focus" line. Solve for g. Take care to watch the units carefully to help avoid mistakes. Sum of cost must be "cents", and total pounds must be pounds.
Based on that, initial equation here (but start by yourself first):