Q)
In a population study of 1500 Indian rivers the following data were reported: 520 were polluted by sulphur compounds, 335 were polluted by phosphates, 425 were polluted by crude oil, 100 were polluted by both crude oil and sulphur compounds; 180 were polluted by both sulphur compounds and phosphates, 150 were polluted by both phosphates and crude oil and 28 were polluted by sulphur compounds, phosphates and crude oil.\[\]
i) Find the number of rivers which were polluted by atleast one of the three impurities.\[\]
ii) Find the number of rivers which were polluted by exactly one of the three impurities.
1 Answer
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