a student takes his examination in 4 subjects-A,B,C,D To qualify he must pass in A and at least 2 other - Maths - Probability

Question

a student takes his examination in 4 subjects-A,B,C,D To qualify
he must pass in A and at least 2 other subjects His chances of
Passing in A,B,C,D are 4/5, 3/4, 5/6, 2/3 respectively Find the
chances of his qualifying

Vipin Verma · Accepted Answer

Given P(A)=45, P(B)=34, P(C)=56, P(D)=23According to the condition
the student will qualify when he pass in Sub A and at least 2
subjectSo, Prob that he will qualify=He pass in A and (Pass in BC
or CD or BD or BCD)=P(A)[P(B)P(C)+P(C)P(D)+P(B)P(D)+
P(B)P(C)P(D)]=4534×56+56×23+34×23+34×56×23=4558+59+12+512=4545+40+36+3072=4515172=15190

a student takes his examination in 4 subjects-A,B,C,D.To qualify he must pass in A and at least 2 other subjects. His chances of Passing in A,B,C,D are 4/5, 3/4, 5/6, 2/3 respectively. Find the chances of his qualifying.