## Question

### Solution

Correct option is

105

We can post the first letter in 10 ways, the second letter in 10 ways and so on. Thus, the number of ways of posting 5 letters in 10 letter boxes is 10 × 10 × 10 × 10 × 10 = 105.

#### SIMILAR QUESTIONS

Q1

The number of rational numbers lying in the interval (2008, 2009) all whose digits after the decimal point are non-zero and are in deceasing order is

Q2

The number of positive integral solutions of the equation is

Q3

The exponent of 7 in 100C50 is

Q4

In the certain test there are n questions. In this test 2k students gave wrong answers to at least (n – k) questions, where k = 0, 1, 2, …, n. If the total number of wrong answer is 4095, then value of n is

Q5

If n > 1 and n divides (n – 1)! + 1, then

Q6

In a group of 8 girls, two girls are sisters. The number of ways in which the girls can sit so that two sisters are not sitting together is

Q7

The number of words that can be formed by using the letters of the word MATHEMATICS that start as well as end with T is

Q8 Q9

The number of subsets of the set A = {a1a2, … an} which contain even number of elements is

Q10

The number of five digit telephone numbers having at least one of their digits repeated is