In a city 20 percent of population travels by car, 50 percent travels by bus and 10 percent travels

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1.Set Theory

easy

In a city $20$ percent of the population travels by car, $50$ percent travels by bus and $10$ percent travels by both car and bus. Then persons travelling by car or bus is......$\%$

A

$80$

B

$40$

C

$60$

D

$70$

Solution

(c) $n(C) = 20, n(B) = 50, n(C \cap B) = 10 $

Now $n(C \cup B) = n(C) + n(B) -n(C \cap B) $

$= 20 + 50 -10 = 60.$

Hence, required number of persons $= 60\%.$

Standard 11

Mathematics

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