In a class of students, like maths, like physics and like both. A student who likes physics is chosen. What is the probability that this student also likes maths?
Answer and explanation
Correct answer: B.
- Step 1: The condition restricts attention to the students who like physics.
- Step 2: Of these, also like maths, so the probability is .
Answer
.
Why not the others: : is the chance that a maths lover also likes physics, with the groups the wrong way round. : is the chance a random student likes both. : is the chance a random student likes physics.
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