X=4. Hope this is the one you wanted me to answer.
F(x) = 12/(4x+2)
x = -1
f(-1) = 12 / [4(-1)+2]
f(-1) = 12 / (-4+2)
f(-1) = 12 / -2
f(-1) = -6
A and B are dependent events.
The general probabilities of each event to happen separately is 36% for event A and 25% for event B. When considering that Chris passes one before passing the other, indicates that whether he gets the first light open or not will affect if he gets the other one also open or not. This can even be seen by noticing how the probability of Chris getting both red lights is 9%, a much inferior probability then considering both lights separately which means that one event has influence over the other.
