If two events A and B $ P( A \cup B ) = 0.5\: and \: P(A \cap B ) = 0.4$ then $ P(A')+P(B')=$

Question

$\begin {array} {1 1} (1)\;0.8 & \quad (2)\;1.25 \\ (3)\;1.1 & \quad (4)\;none\: of \: these \end {array}$