Of hundred people who read at least one of the three movie magazines are surveyed to study the readership pattern. It is found that 80 read Filmfare, 50 read Stardust and 30 read Cineblitz. Five read all three. How many read exactly two magazines?
Of hundred people who read at least one of the three movie magazines are surveyed to study the readership pattern. It is found that 80 read Filmfare, 50 read Stardust and 30 read Cineblitz. Five read all three. How many read exactly two magazines?
This is classical inclusion - exclusion principle.
http://en.wikipedia.org/wiki/Inclusi...sion_principle
100 = 80 +50 + 30 - (people who read two magazines) + (people who read three magazines)
100 = 165 - (the number you are looking for)