Solving Probability problems is easy using the Probability Solver as part of the Statistics Made Easy App for the TiNspire at www.TiNspireApps.com. Solve for the unknown probability by leaving that box blank, find probability for AND & OR events, test for Independence, check if Disjoint.
First , Select Option A in the menu :
Next, fill in all but one box as shown below. View the results in the bottom box. That simple.
Scrolling down the further shows more detailed solutions.