Q.

A six faced die is biased such that 3 × P(a prime number) = 6 × P(a composite number) = 2 × P(1). Let X be a random variable that counts the number of times one gets a perfect square on some throws of this die. If the die is thrown twice, then the mean of X is :

see full answer

Start JEE / NEET / Foundation preparation at rupees 99/day !!

21% of IItians & 23% of AIIMS delhi doctors are from Sri Chaitanya institute !!
An Intiative by Sri Chaitanya

a

511

b

711

c

811

d

311

answer is D.

(Unlock A.I Detailed Solution for FREE)

Ready to Test Your Skills?

Check your Performance Today with our Free Mock Test used by Toppers!

Take Free Test

Detailed Solution

detailed_solution_thumbnail

Let P( a prime number )2=P( a composite )1=P(1)3=k

So, P(a prime number) = 2k,

      P(a composite number) = k,

&   P(1) = 3k

&  3 × 2k + 2 × k + 3k = 1

k=111

P(success) = P(1 or 4)=3k+k=411

Number of trials, n = 2

 mean = np =2×411=811

Watch 3-min video & get full concept clarity

tricks from toppers of Infinity Learn

score_test_img

Get Expert Academic Guidance – Connect with a Counselor Today!

whats app icon