Q99 / 150 · MHT CET 2026 (18 April Shift 1) · Mathematics

Let $F(x)$ be the cumulative distribution function (c.d.f.) of a continuous random variable $X$. If $F(b) = 0.7$ and $P(X > a) = 0.4$, then the value of $P(a < X < b)$ is ...

  • Correct answer
    A
    $0.1$
  • B
    $0.2$
  • C
    $0.3$
  • D
    $0.5$

Solution

The cumulative distribution function $F(x)$ is defined as $F(x) = P(X \le x)$.

Given $F(b) = 0.7$, we have $P(X \le b) = 0.7$.

We are also given $P(X > a) = 0.4$.

Since $P(X \le a) + P(X > a) = 1$, we get:

$P(X \le a) = 1 - 0.4 = 0.6$

For a continuous random variable, the probability $P(a < X < b)$ is given by:

$P(a < X < b) = P(X \le b) - P(X \le a)$

Substituting the values:

$P(a < X < b) = 0.7 - 0.6 = 0.1$

Answer: $0.1$

Hence, the correct answer is option: 'A'.

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