Trying to help my girlfriend with VB

Guys, here is the deal. Trying to help a girl with practice, but something did not master.
Master could not, even though he had promised. Help out, please.

1. To develop the project, the form and enter the code for the following tasks:

Calculate the percentage of students who do not pass the exam, if you know the total number of students, number of students who passed with no satisfactory estimates, the number of students who passed with satisfactory grades.

2. Run modification forms and event handling code for the command buttons according to their version for the following tasks:

Calculate for each of the N groups of the percentage of students who do not pass the exam, if you know the total number of students, number of students who passed with no satisfactory estimates, the number of students who passed with satisfactory grades in each group.

I will be very grateful to everyone who responds.