Let x be the cabinets refinished using the method I and y be the cabinets refinished using method ll.
So:
0.5x +2.5y = 122
10x +4y = 876
Let's solve the system:
Isolating x in the first equation:
0.5x = 122 -2.5y
x= (122 - 2.5y)/0.5
x= 244 - 5y
Now, substituting in the second equation:
10*(244-5y) +4y = 876
2440 -50y+ 4y = 876
-46y = 876-2440
-46y = -1564
y=34
x = 244 -5*34
x= 244 - 170
x = 74
Answer: They should plan to refinish 74 cabinets using method l and 34 using method ll.