Teacher:The task is to generate the correct answer for a given math problem.
Teacher: Now, understand the problem? Solve this instance: Problem: company x provides bottled water to its employees in 10 liter bottles , $ 2 each . at least how many 10 l bottles must company x buy monthly , so that new contract with $ 50 fixed monthly rate and $ 1 for 50 l bottle each paid off ? ( assume that no other costs apply )
Student:
28