Using the inclusion - exclusion principle, we have:
P(A or B) = P (A) + P (B) - P(A and B)
Substituting, 15/16 = 6/16 + P(B) - 2/16
So P(B) = 11/16.
Alternatively, you can draw a Ven-diagram with two circles sharing an intersection.
Labeling the first circle A and other circle B. You can assume...