"Channel One" is an educational television network for which participating secondary schools are equipped with TV sets in every classroom. It has been found that 70% of secondary schools subscribe to Channel One, where of these subscribers 5% never use Channel One while 25% claim to use it more than 5 times per week.
Find the probability that a randomly selected secondary school subscribes to Channel One and uses it more than 5 times per week.
I have reasoned that
$P(A) = 0.7$ from the number of secondary schools subscribed to channel one
$P(B) = 0.25$ claim to use it more than 5 times per week.
\begin{align} P(A \cup B) &= P(A) + P(B) - P(A \cap B)\\ &= 0.7 + 0.25 - (0.70)(0.25)\\ &= 0.775 \end{align}
What is the correct answer and solution?