Reply To: Hi what is the formula solve this question or any sample

[Susan BrownKeymaster]

Question 7 is all about understanding the basic behavior of voltage and current when you have parallel circuits, particularly what happens when one of the branches fails open.

The material, especially the videos, in Units 4 and 5 of Basic Electricity talk a lot about parallel circuits.

Now, keep in mind that you got 2 of the 4 answers correct (parts 1 and 3).