Probability that exactly one of them fails = A fails & B succeeds (OR) A succeeds & B fails= (0.2)(1-0.3) + (1-0.2)(0.3)=(0.2)(0.7) + (0.8)(0.3)=0.14 + 0.24=0.38Hence Choice A.
Aptitude
Topic: probablity
The probability that A will fail in an examination is 0.2 and that of B failing is 0.3 . The probability that exactly one of them will fail is a) 0.38b) 0.35 c) 0.42d) 0.62e) 0.32
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