Question 814
let GROUND ROUND to be mixed = x lbs
when x lbs of GROUND ROUND mixed with 20 LBS OF GROUND CHUCK, total of (20+x) lbs.

price of GROUND CHECK = 1.75
price of GROUND ROUND= 2.45
price of the mix = 2.05

total cost of the mix  = 2.05 * (20+x)
the cost of the GROUND ROUND,GROUND CHECK  used to mix = 20 * 1.75 + x * 2.45

2.05(x+20) = 20 * 1.75 + x * 2.45
2.05x + 41 = 35 + 2.45x
2.05x - 2.45x = 35-41
-0.4x = -6
x= 15

Therefore 15lbs of GROUND ROUND has to be mixed.

:-)