i have statistics homework and im dead

"Let P (A) = 0.5, P (B) = 0.7, P ( A and B ) = 0.4

Find the probability:
c) Either A or B will occur
d) that neither A nor B will occur

if anybody is able to help, i have two more i need assistance on, but this is all i will be posting for now.

Question

i have statistics homework and im dead

"Let P (A) = 0.5, P (B) = 0.7, P ( A and B ) = 0.4

Find the probability: 
c) Either A or B will occur
d) that neither A nor B will occur

if anybody is able to help, i have two more i need assistance on, but this is all i will be posting for now.

amistre64 · Answer

does P(A)+P(B) = 1?

amistre64 · Answer

|dw:1442529707659:dw|

amistre64 · Answer

lets say we wanted to count X+Y, to obtain all the values

X = 1+2
Y = 2+3

but X+Y is all there is, so its total should be:  1+2+3

but notice we are duplicating what they have in common, so we have to adjust for that

X+Y - (XandY) gives us the total

anonymous · Answer

oh god thank you so much im v sorry for the late reply i just zoned out and tried to figure out how i was going to pass this test if i couldnt even do the prep homework thank you again