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If a random variable X has the following probability distribution:

X0123
P(X)KK/2K/4K/8

then,

Match List-I with List-II

List-IList-II
(A) The value of K is(I) 2/15
(B) P(0 < X < 2) is(II) 1/15
(C) P(1 < X < 3) is(III) 8/15
(D) P(X > 2) is(IV) 4/15

Choose the correct answer from the options given below:

Solution

Correct Option: 3

Given probability distribution:

  • P(X=0)=KP(X=0) = K
  • P(X=1)=K/2P(X=1) = K/2
  • P(X=2)=K/4P(X=2) = K/4
  • P(X=3)=K/8P(X=3) = K/8

All probabilities must sum to 1:

K+K2+K4+K8=1K + \frac{K}{2} + \frac{K}{4} + \frac{K}{8} = 1

Converting to common denominator 8:

8K8+4K8+2K8+K8=1\frac{8K}{8} + \frac{4K}{8} + \frac{2K}{8} + \frac{K}{8} = 1

15K8=1\frac{15K}{8} = 1

K=815K = \frac{8}{15}

Therefore, (A) matches with (III)


For P(0<X<2)P(0 < X < 2):

The inequality 0<X<20 < X < 2 includes only X=1X = 1:

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

=K2= \frac{K}{2}

=8/152= \frac{8/15}{2}

=815×12= \frac{8}{15} \times \frac{1}{2}

=415= \frac{4}{15}

Therefore, (B) matches with (IV)


For P(1<X<3)P(1 < X < 3):

The inequality 1<X<31 < X < 3 includes only X=2X = 2:

P(1<X<3)=P(X=2)P(1 < X < 3) = P(X=2)

=K4= \frac{K}{4}

=8/154= \frac{8/15}{4}

=815×14= \frac{8}{15} \times \frac{1}{4}

=215= \frac{2}{15}

Therefore, (C) matches with (I)


For P(X>2)P(X > 2):

The inequality X>2X > 2 includes only X=3X = 3:

P(X>2)=P(X=3)P(X > 2) = P(X=3)

=K8= \frac{K}{8}

=8/158= \frac{8/15}{8}

=815×18= \frac{8}{15} \times \frac{1}{8}

=115= \frac{1}{15}

Therefore, (D) matches with (II)


Final matching:

  • (A) → (III): K=815K = \frac{8}{15}
  • (B) → (IV): P(0<X<2)=415P(0 < X < 2) = \frac{4}{15}
  • (C) → (I): P(1<X<3)=215P(1 < X < 3) = \frac{2}{15}
  • (D) → (II): P(X>2)=115P(X > 2) = \frac{1}{15}

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