Embibe Experts Solutions for Exercise 3: EXERCISE 14.3

The probability that a teacher will give an unannounced test during any class meeting is $\frac{1}{5}$. If a student is absent twice, then the probability that the student will miss at least one test, is

Three letters are written to three different persons and addresses on the three envelopes are also written. Without looking at the addresses, the letters are kept in these envelopes. The probability that all the letters are not placed into their right envelopes is

$10$ bulbs out of a sample of $100$ bulbs manufactured by a company are defective. The probability that $3$ out of $4$ bulbs, bought by a customer will not be defective, is

$n$ letters are written to $n$ different persons and addresses on the $n$ envelopes are also written. If the letters are placed in the envelopes at random, the probability that at least one letter is not placed in the right envelope, is

$6$ girls and $5$ boys sit together randomly in a row, the probability that no two boys sit together, is

The probability of guessing correctly at least $8$ out of $10$ answers on a true-false examination, is

Three of the six vertices of a regular hexagon are chosen at random. The probability that the triangle with three vertices is equilateral, equals

One mapping is selected at random from all the mappings of the set $A=\left\{1,2,3,\dots ,n\right\}$ into itself. The probability that the mapping selected is one to one mapping is given by