Question

Find the number of integers greater than 7000 that can be formed with the digits 3, 5, 7, 8 and 9, no digit being repeated.

Solution

Correct option is

192

A five digit integer is always greater than 7000. The number of such integers is 5P5 = 5! = 120. For a four digit integer to be greater than 7000, it must being with 7, 8 or 9. The number of such integers is 120 + 72. Hence, the required number of such integers is 120 + 72 = 192.

SIMILAR QUESTIONS

Q1

The number of positive integers n such that 2n divides n! is

Q2

A class contains 4 boys and g girls. Every Sunday five students, including at least three boys go for a picnic to Appu Ghar, a different group being sent every week. During, the picnic, the class teacher gives each girl in the group a doll. If the total number of dolls distributed was 85, then value of g is    

Q3

The sum of the factors of 9! Which are odd and are of the form 3m + 2, where m is a natural number is 

Q4

Sum of all three digit numbers (no digit being zero) having the property that all digit are perfect squares, is

Q5

Let S = {1, 2, 3, ... n}. if X denote the set of all subsets of S containing exactly two elements, then the value of   

Q6

Let a be a factor of 120, then the number of integral solution of x1x2x3 = a is 

Q7

There are 15 points in a plane of which exactly 8 are collinear. Find the number of straight lines obtained by joining there points.   

Q8

If n is the number of ways in which an examiner can assign 30 marks to 8 questions, giving not less than 2 marks to any quation find n/40.

Q9

Find the number of rectangles that you can find on a chessboard.

Q10

Ten persons, amongst whom are A, B and C, are to speak at a function. If n is the number of ways in which it can be done if A wants to speak before B, and B wants to speak before C find n/800.