The probabilities of three events A, B and C are given P(A) = 0 ....

P\left(A \cup B \cup C\right) = P ( A ) + P ( B ) + P ( C ) - P ( A \cap B ) - P ( B \cap C ) - P ( C \cap A ) + P \left(A \cap B \cup C\right)

$⇒ \alpha = 1 . 4 - p ( A \cap B ) - \beta$

$⇒ \alpha + \beta = 1 . 4 - p ( A \cap B )$....(1)

again

$P ( A \cup B ) = P ( A ) + P ( B ) - P ( A \cap B )$

$⇒ P ( A \cap B ) = \cdot 2$......(2)

by $\left(1\right)$ and \left(2\right)

$\alpha = 1 . 2 - \beta$

now

$0 . 85 \le \alpha \le 0 . 95$

$⇒ 0 . 85 \le 1 . 2 - \beta \le 0 . 95 ⇒ \beta \in \left[0 . 25, 0 . 35\right]$