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प्रश्न
The probability of guessing the correct answer to a certain test questions is\[\frac{x}{12}\] If the probability of not guessing the correct answer to this question is\[\frac{ 2}{3}\] then x =
विकल्प
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उत्तर
Probability of guessing a correct answer to a certain question is `x/12`
Probability of not guessing a correct answer to a same question `2/3`
TO FIND: The value of x
CALCULATION: We know that sum of probability of occurrence of an event and probability of non occurrence of an event is 1.
If E is an event of occurrence and `overlineE` is its complementary then `P(overlineE)+P(overline E)=1`
According to the question we have
`x/12+2/3=1`
`(x+8)/12=1`
`x+8=12`
`x=4`
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