The mean of the numbers obtained on throwing a die having written 1 on three faces, 2 on two faces and 5 on one face is

Given: A die having written 1 on three faces, 2 on two faces and 5 on one face.

Let X be the random variable representing a number on given die.

Then X can take any value of 1, 2 or 5.

The total numbers is six.

Now

P(X = 1)

P(X = 2)

P(X = 5)

Hence, the required probability distribution is,

Therefore Expectation of X E(X):

⇒ E(X) = 2

Hence, the correct answer is (B).