In a college, 30% students fail in physics, 25% fail in Mathematics and 10% fail in both. One student is chosen at random. The probability that she fails in physics if she has failed in mathematics is

2/5

The correct answer is Option (1) → 2.5 **

Given:

$P(\text{Physics fail}) = 0.30$

$P(\text{Math fail}) = 0.25$

$P(\text{Fail both}) = 0.10$

We need: $P(\text{Physics fail} \mid \text{Math fail})$

Use conditional probability:

$P(\text{Physics fail} \mid \text{Math fail}) = \frac{P(\text{Fail both})}{P(\text{Math fail})}$

$= \frac{0.10}{0.25}$

$= 0.40$

The required probability is $0.40$.