Break-even point

Bob's Burritos sells all of their burritos for $4.50 while the cost is only $3.00. If the monthly fixed expense is $1,500, how many burritos must Bob sell a month to breakeven?

Need the exact number of burritos to sell in a month in order to break-even, I must show how to get that number, and I am having a problem with the formula and whether or not which price to use