1
JEE Main 2022 (Online) 27th June Evening Shift
Numerical
+4
-1

Let S = {E1, E2, ........., E8} be a sample space of a random experiment such that $$P({E_n}) = {n \over {36}}$$ for every n = 1, 2, ........, 8. Then the number of elements in the set $$\left\{ {A \subseteq S:P(A) \ge {4 \over 5}} \right\}$$ is ___________.

2
JEE Main 2022 (Online) 26th June Evening Shift
Numerical
+4
-1

If the probability that a randomly chosen 6-digit number formed by using digits 1 and 8 only is a multiple of 21 is p, then 96 p is equal to _______________.

3
JEE Main 2022 (Online) 24th June Evening Shift
Numerical
+4
-1
Out of Syllabus

In an examination, there are 10 true-false type questions. Out of 10, a student can guess the answer of 4 questions correctly with probability $${3 \over 4}$$ and the remaining 6 questions correctly with probability $${1 \over 4}$$. If the probability that the student guesses the answers of exactly 8 questions correctly out of 10 is $${{{{27}k}} \over {{4^{10}}}}$$, then k is equal to ___________.

4
JEE Main 2021 (Online) 1st September Evening Shift
Numerical
+4
-1
Let X be a random variable with distribution.

x $$-$$2 $$-$$1 3 4 6
P(X = x) $${1 \over 5}$$ a $${1 \over 3}$$ $${1 \over 5}$$ b

If the mean of X is 2.3 and variance of X is $$\sigma$$2, then 100 $$\sigma$$2 is equal to :