Answer:
P(A or B) = 0.9.
Step-by-step explanation:
This is a question of Venn probabilities.
We use the following relation to solve this question.
[tex]P(A \cup B) = P(A) + P(B) - P(A \cap B)[/tex]
The exercise states that:
[tex]P(A) = 0.7, P(B) = 0.6, P(A \cap B) = 0.4[/tex]
Then
[tex]P(A \cup B) = P(A) + P(B) - P(A \cap B) = 0.7 + 0.6 - 0.4 = 0.9[/tex]
The answer is:
P(A or B) = 0.9.