Skip to main contentSkip to solution

If the random variable X has the following probability distribution:

X012otherwise
P(X)k3k5k0

Match List-I with List-II

List-IList-II
(A) k(I) 139\frac{13}{9}
(B) E (X)(II) 49\frac{4}{9}
(C) P (X ≤ 1)(III) 89\frac{8}{9}
(D) P (1 ≤ X ≤ 2)(IV) 19\frac{1}{9}

Choose the correct answer from the options given below:

  1. (A) - (II), (B) - (I), (C) - (IV), (D) - (III)
  2. (A) - (IV), (B) - (I), (C) - (II), (D) - (III)
  3. (A) - (IV), (B) - (II), (C) - (I), (D) - (III)
  4. (A) - (III), (B) - (II), (C) - (I), (D) - (IV)

Solution

✅ Correct Option: 2

The probability distribution has X taking values 0, 1, or 2, with probabilities k, 3k, and 5k respectively.

The sum of all probabilities must equal 1:

P(X=0)+P(X=1)+P(X=2)=1P(X = 0) + P(X = 1) + P(X = 2) = 1

k+3k+5k=1k + 3k + 5k = 1

9k=19k = 1

k=19k = \dfrac{1}{9}

(A) matches with (IV)


The expected value is calculated as:

E(X)=(0×k)+(1×3k)+(2×5k)E(X) = (0 \times k) + (1 \times 3k) + (2 \times 5k)

E(X)=0+3k+10kE(X) = 0 + 3k + 10k

E(X)=13kE(X) = 13k

E(X)=13×19E(X) = 13 \times \dfrac{1}{9}

E(X)=139E(X) = \dfrac{13}{9}

(B) matches with (I)


For X ≤ 1, the random variable can be 0 or 1:

P(X≤1)=P(X=0)+P(X=1)P(X \leq 1) = P(X = 0) + P(X = 1)

P(X≤1)=k+3kP(X \leq 1) = k + 3k

P(X≤1)=4kP(X \leq 1) = 4k

P(X≤1)=4×19P(X \leq 1) = 4 \times \dfrac{1}{9}

P(X≤1)=49P(X \leq 1) = \dfrac{4}{9}

(C) matches with (II)


For 1 ≤ X ≤ 2, the random variable can be 1 or 2:

P(1≤X≤2)=P(X=1)+P(X=2)P(1 \leq X \leq 2) = P(X = 1) + P(X = 2)

P(1≤X≤2)=3k+5kP(1 \leq X \leq 2) = 3k + 5k

P(1≤X≤2)=8kP(1 \leq X \leq 2) = 8k

P(1≤X≤2)=8×19P(1 \leq X \leq 2) = 8 \times \dfrac{1}{9}

P(1≤X≤2)=89P(1 \leq X \leq 2) = \dfrac{8}{9}

(D) matches with (III)


The correct matching is:

(A) → (IV): k=19k = \dfrac{1}{9}

(B) → (I): E(X)=139E(X) = \dfrac{13}{9}

(C) → (II): P(X≤1)=49P(X \leq 1) = \dfrac{4}{9}

(D) → (III): P(1≤X≤2)=89P(1 \leq X \leq 2) = \dfrac{8}{9}

Therefore, the answer is Option 2: (A) - (IV), (B) - (I), (C) - (II), (D) - (III)

Keyboard Shortcuts

  • Left arrow: Previous question
  • Right arrow: Next question
  • S key: Jump to solution
  • Q key: Jump to question