In a locality, two-thirds of the people have cable-TV, one-fifth have VCR, and one-tenth have both, what is the fraction of people having either cable TV or VCR?
Fraction of people who watch cable tv only= (2/3 - 1/10) = 17/30
Fraction of people who watch VCR only = (1/5 - 1/10) = 1/10
Therefore fraction of people who watch either cable or vcr = 17/30 + 1/10 = 20/30 = 2/3
So 2/3 is the Correct answer.