I already know how to do number 1, 2 and 3 so I dont need equations or explanations, Really I just need an explanation to number 4, I only provided them all because they are all connected.

Quickfibre Phones has just opened its doors. The new retail store sells refurbished phones at a significant discount from market prices. The phones cost Quickfibre $35 to purchase and require additional variable costs of $31, which includes labor for refurbishing of $25 and wages for sales personnel of $6. The newly refurbished phones are resold to customers for $96. Rent on the retail store costs the company $4,200 per month.

1. How many phones does quickfibre have to sell each month to break even?

2. If quickfibre wants to earn $2,400 per month after all expenses, how many phones does the company need to sell.

3. Quickfibre can purchase already refurbished phones for $45. This would mean that all labor required to refurbish the phones could be eliminated. What would Quickfibres new breakeven point be if it decided to purchase the phones already refurbished?

4. Instead of paying the monthly rental fee for the rental space, Quickfibre has the option of paying its landlord a 25% commission on sales. Assuming the original facts in the problem, at what sales level would quickfibre be indifferent between paying a fixed amount of monthly rent and paying a 25% commission on sales?