Question

In a committee, 50 people speak French, 20 speak Spanish and 10 speak both Spanish and French. How many speak atleast one of these two languages?

Answer 1

Let F = set of people speaking French 

S = set of people speaking Spanish. 

Then n(S) = 20, n(F) = 50 n(F∩S) = 10 

∴ n(F∪S) = n(S) + n(F)-n(F∩S) 

= 20 + 50-10 = 60 

∴ 60 people speak French or Spanish or both.