Bob's Company has two options to produce a product:

1. Bobs could build their own factory for production, which requires $250,000 fixed cost and $15 variable cost per unit.
2. Bobs could outsource the production to Harrys Company, which incurs $125,000 fixed cost and $35 variable cost per unit.

Assume Bobs can sell every unit it produces.

How many units of product will Bobs have to sell before the self-production method (a) becomes more cost-efficient than outsourcing

Show your work.