A solution to last week's challenge can be found here. 
The Ideal Gas law is a staple of Chemistry classes around the world. You may recall that it is defined as PV=nRT; where P = pressure, V = volume, n = the number of moles, R = the ideal gas constant, and T = temperature.
This week's challenge is to create an app that requires an end user to select 3 checkboxes and enter values, then produces the final variable and units as a result.
For the sake of simplicity, we will use static units for all variables. Pressure in ATM, Volume in Liters Temperature in Kelvin, and R = 0.082057338. Use 3 decimal places on the inputs. You can check your math here.
Bonus: Add in error messages if the user selects too few or too many checkboxes.
