This page is the calculation of the "Alpha Dairy Mobile" guide. You can see it here: Guides and Other Walkthroughs
Noted that some numbers here are round up.
Let's start with the consumption of your caravan:
According to the Food page once a person is fed entirely on cow milk, they'll drink 3.03 milk per day and need no water. 18 people will consume 54.54 milk per day.
Vehicles only consume fuel, lubricant and water when they're moving. Five Umi Alpha travel from Qubba to Patrolton(and vice versa) will consume 985 fuel, 0.8 lubricant and 0.8 water. After a twenty-day-rotation(two trips) you'll consume 1970 fuel, 1.6 lubricant and 1.6 water.
Now we can talk about the money, I'll start with dairy product:
Dairy Product ProfitEdit
Every cows are different but in average each female cow consume 6 forage and 10 water, produce 6 milk. Forage cost $1.5 and water cost $0.5 in Qubba. So one milk cost (6*1.5+10*0.5)/6=2.33.
Every day cheese industry consume 55 milk, produce 5 cheese, maintenance fee is $229. So one cheese cost (2.3*55+229)/5=71.1
Twenty cows produce 120 milk per day but people drink 54.54 milk. So you have 65.46 spare milk. 55 of them will be made into cheese and 10.46 will be sold directly.
In Patrolton milk's selling price is $27.55. Cheese price, however, will change: At first it's only $567.71, but after a few days people will started to fall in love with it and from now on the price will explode to $1116.05! So at first the overall dairy product profit will be (567.71-71.1)*5+(27.55-2.33)*10.46=2746.85, but after a few days it'll be (1116.05-71.1)*5+(27.55-2.33)*10.46=5488.55!
Next is the lubricant:
Every day oil refinery consume 200 petroleum, produce 8 lubricant and 100 fuel, maintenance fee is $3090. Petroleum cost $20 in Patrolton. So one lubricant cost (20*200+3090)/8=886.25.
1.6 lubricant is used every 20 days, equals to 0.08 lubricant per day. So you have 7.92 spare lubricant. In Patrolton lubricant's selling price is $1246.49. So lubricant profit will be (1246.49-886.25)* 7.92=2853.1
(Noted that fuel is considered as side product here so it's considered free. But since your truck will consume almost all of them, you can completely ignore fuel when calculating profit.)
At last, 1.6 engine water is used every 20 days, equals to 0.08 water per day. Water cost $0.5 in Qubba. So the cost is (0.5*0.8*2)*/20=0.04. Now we can finally calculate the total profit.
In the first few days it'll be 2853.1+2746.85-0.04=5599.91, equals to $39199.37 per week.
After a while it'll be 2853.1+5488.55-0.04=8341.61, equals to $58391.27 per week.