Question

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 = 

पर्याय

• 2

•  3

•  4

• 6

Answer 1

 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`