Lars, a shoe salesman, is paid every two weeks, whereas Tom receives a commission for each pair of shoes he sells. Evidently, Lars is paid on a schedule of reinforcement, and Tom on a schedule of reinforcement.

Lars is paid on a FIXED INTERVAL schedule of reinforcement, and Tom on a FIXED RATIO schedule of reinforcement.

Explanation:

A fixed interval payment schedule refers to being paid after a set amount of time. In this case Lars gets paid an amount every two weeks.

A fixed ratio payment schedule refers to being paid a fixed percent of the total sales made. In this case, Tom is paid a certain commission for every pair of shoes that he sells.

This question is based on the ideal gas law , where is the pressure, is the volume, is number of moles, is the gas constant which can take many values depending on the units. In this problem we will use to get our pressure in atm. So we male P the subject of the formula