JEE Main 2020 (Online) 8th January Morning Slot | Probability Question 155 | Mathematics

In a workshop, there are five machines and the probability of any one of them to be out of service on a day is $${{1 \over 4}}$$ . If the probability that at most two machines will be out of service on the same day is $${\left( {{3 \over 4}} \right)^3}k$$, then k is equal to :

$${{{17} \over 4}}$$

$${{{17} \over 2}}$$

$${{{17} \over 8}}$$

JEE Main 2020 (Online) 7th January Morning Slot

MCQ (Single Correct Answer)

-1

An unbiased coin is tossed 5 times. Suppose that a variable X is assigned the value of k when k consecutive heads are obtained for k = 3, 4, 5, otherwise X takes the value -1. Then the expected value of X, is :

$$ - {3 \over {16}}$$

$$ - {1 \over 8}$$

$${1 \over 8}$$

$${3 \over {16}}$$

JEE Main 2019 (Online) 12th April Evening Slot

MCQ (Single Correct Answer)

-1

Out of Syllabus

For an initial screening of an admission test, a candidate is given fifty problems to solve. If the probability that the candidate solve any problem is $${4 \over 5}$$ , then the probability that he is unable to solve less than two problems is :

$${{164} \over {25}}{\left( {{1 \over 5}} \right)^{48}}$$

$${{316} \over {25}}{\left( {{4 \over 5}} \right)^{48}}$$

$${{201} \over 5}{\left( {{1 \over 5}} \right)^{49}}$$

$${{54} \over 5}{\left( {{4 \over 5}} \right)^{49}}$$

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