Question 566317
Let 'c' be the number of pounds of cheaper nuts and 'e' the number of pounds of expensive nuts. Then we have the equations c+e=10 and (3.5*c+5*e)/(c+e)=4. Substitute c+e=10 and c=10-e into the second equation to get (3.5*(10-e)+5*e)/(10)=4. Solving, we get e=3.33 and c=6.67.