In a committee, 50 people speak French, 20 speak Spanish and 10 speak both Spanish and French. How many speak at least one of these two languages?
Let A = set of people who can speak French. n(A) = 50
....(i)
B = set of people who speak Spanish n(B) = 20 ....(ii)
Number of people who speak both languages = ....(iii)
Number of people who speak at least one of the two languages ....(iv)
We know that
∴
Hence, the number of people who speak at least one of the two languages