Back when I went to school, you had to think thins through from the start to finish. today we use a computer program or a chart.
I don't think the problem was put in a proper equation.
put it this way:
50+50X0+1=1
50+50X0+1=51
50+50X0+1=101 this equals 100 not 101 .
Now find the value of each step of the way.
Then put it in the right equation each time.
As for ranch management. Yes we have a goal of weight at weaning or at selling time. There are models to help you get there, but there are also variables. We set our expectations on our experience. If we are good business men we have to plan around that, and use what we have.
I always enjoyed working out feed rations with the computer, but for my weaning and backgrounding of calves and my brood cow rations. It was a good guide, and a way to check how well you were doing. As far as the cow rations went, I found that if you are a good herdsman. the old cow will just about tell you she needs as well as a feed chart. I had a fellow working for me that watched what the cows were eating, if it was cold, he fed an extra bale if they left a little to much , he cut back. about 3 weeks before calving time a cow has less capacity for hay, intake drops off, feed better feed then.
As far as tractors and equipment, we do have to try to estimate the hours we will use them and the number of years we will keep them and their value after that. It is hard to determine what return they will make on your investment.
Back in 1999, I bought a second hand 2550 NH swather, I figured if I used it 10 years, I would have to do a few hundred acres of custom work to make it pay out. I did do custom work the first year, but with time spent doing that it didn't pay out. Well I still have the old swather, but I don't think it ever paid for itself.
Does that answer your question Sweet Basil.