John bought 50000 chairs for resale. Each chair cost $10 and he prices the chairs at $20 each. How many chairs does John need to sell to break even?
The total cost of the chairs is 50000*$10 = $<<50000*10=500000>>500,000
For every chair John sell, he makes a profit of $20 - $10 = $<<20-10=10>>10
In order for John to break even he needs to sell $500,000 / $10 = <<500000/10=50000>>50,000 chairs. Answer: \boxed{50,000}.