# In a pollution study of 1500 Indian rivers the following data were reported. 520 were polluted by sulphur compunds, 335 were polluted by phosphorous, 425 were polluted by crude oil, 100 were polluted by both crude oil and sulphur compunds, 152 were polluted by sulphate and phosphate compounds only, 150 were polluted by phosphate and crude oil, and 28 were polluted by all 3 compounds. How many of the rivers were polluted by exactly one of the 3 impurities?

### Asked by Varshini Srinivasan | 20th Jun, 2014, 07:07: PM

Expert Answer:

### U represents the collection of all the Indian rivers.
S represents the rivers polluted by sulphur compunds.
P represents the rivers polluted by phosphorous.
C represents the rivers polluted by crude oil.

The number of rivers polluted by sulpher compound only is given by

The number of rivers polluted by Crude oil only is given by

The number of rivers polluted by phosphate compound only is given by

Total number of rivers polluted by exactly one of the 3 impurities

=296+203+61=560

The number of rivers polluted by Crude oil only is given by

The number of rivers polluted by phosphate compound only is given by

### Answered by Vimala Ramamurthy | 23rd Jun, 2014, 03:35: PM

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