A student has a probability of getting failed in physics and maths by 20% and 10%.what is the probability of that student of getting failed in one subject?

1 Answer
Jan 31, 2018

#0.26#

Explanation:

#"P(A xor B) = P(A) + P(B) - 2 P(A and B)"#
#"Name A = 'fail physics' and B = 'fail maths', then we have"#
#"P(A xor B) = "0.2 + 0.1 - 2*0.2*0.1 = 0.26#
#"So we must assume independence between the two results."#
#"If event A and B are independent then"#
#P(A and B) = P(A) * P(B)#
#"xor stands for exclusive or, this means or with the additional"#
#"constraint that both events together must not happen."#