Real-Life Math -- Solution
First, figure out what you pay now:
2 days x 8 hours x $35 per hour = $560 per week
$560 x 4 weeks = $2,240 per month
It costs you $2,240 a month to rent studio space and buy glass.
Now figure out what the new arrangement will cost:
$1,500 rent + $270 loan payment + $1,000 fuel + $350 glass = $3,120
It would cost $3,120 per month to run your own studio.
Calculate the total number of hours you'll need to rent out the studio each week to break even:
$3,120 total cost / $35 per hour = 89.14 hours
89.14 hours / 4 weeks = 22 hours per week (rounded off)
You'll need to rent out the studio 22 hours a week to cover your costs. You have 2 glass blowers interested in renting space from you, so each would have to rent 11 hours a week to add up to the 22 hours a week.
Calculate how much time each week you will have to do your own glass blowing:
40 hours in a week - 22 hours rented = 18 hours for your own work
You'll have 18 hours a week to work in the studio. This is two hours more a week than you have now, and it would be basically free to you, since your renters are covering the full cost of operating the studio.
But what happens if you get only one person to rent from you?
11 hours x $35 per hour = $385 per week
$385 per week x 4 weeks = $1,540 a month
$3,120 total costs - $1,540 from rent = $1,580 per month that you pay
It will cost you $1,580 a month to run the studio if you can get only one person to rent from you. That's still less than what you're paying now to rent.
You decide to open your own studio. Congratulations!