Nitin has taken the subjects mathematics, physics and chemistry. The probability of him getting grade A in these subjects are respectively 0.2, 0.3 and 0.9. Getting grades in different subjects are regarded as independent events. The probability of getting A grade by him, either in mathematics or physics, is
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 0.44
Given:
$P(A_{\text{Math}}) = 0.2$, $P(A_{\text{Physics}}) = 0.3$
Required: Probability that Nitin gets grade A in either mathematics or physics.
Let the event be $P(A_{\text{Math}} \cup A_{\text{Physics}})$
Using formula: $P(A \cup B) = P(A) + P(B) - P(A \cap B)$
$P(A_{\text{Math}} \cup A_{\text{Physics}}) = 0.2 + 0.3 - (0.2 \cdot 0.3) = 0.5 - 0.06 = 0.44$