Question

In a survey of 5000 persons in a town, it was found that 45% of the persons know language a, 25% know language b, 10% know language c, 5% know languages a and b, 4% know languages b and c, and 4% know languages a and


c. if 3% of the persons know all the three languages, find the number of persons who knows only language


a.

Answer 1

Those who know language a = 45% x 5000

                                               = 2250


Those who know language b = 25% x 5000

                                               = 1250


Those who know languages a and b = 5% x 5000

                                                           = 250



Those who know a alone = 2250 - 250

                                         = 2000