In class XI of a school 40% of the students study Mathematics and 30% study Biology, 10% of the class study both Mathematics and Biology. If a student is selected at random from the class, find the probability that he will be studying mathematics or Biology.

Explanation

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Let M and B be the events of .studying Mathẹmatics and Biplogy respectively.
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P(M)=40/100, P(B)=30/100, P(A and B)=10/100 cdot therefore ddots
Required probability =P(A or B)=P(A uu B)=P(A)+P(B)-P(A nn B)
therefore 40/100+30/100-I 0/100=60/100=0.6
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