Q17 of 63 Page 976

In class, 30% of the students offered mathematics 20% offered chemistry and 10% offered both. If a student is selected at random, find the probability that he has offered mathematics or chemistry.

Given: Math students = 30%


Chemistry Students = 20%


Math & Chemistry both = 10%


To Find: P(Math or Chemistry)


Now, P(Math)


P(Chemistry)


P(Math ∩ Chemistry)


We know that,


P(A ∪ B) = P(A) + P(B) – P(A ∩ B)


Therefore,


P(Math ∪ Chemistry) = 0.30 + 0.20 – 0.10 = 0.40


Hence, number of students studying math or chemistry are 40%.


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