Mr. A forgot to write down a very important phone number. All he remembers is that it started with 713 and that the next set of 4 digit involved are 1,7 and 9 with one of these numbers appearing twice.He guesses a phone number and dials randomly. The odds in favour of dialing the correct telephone number, is

A boy forgets the last two digits of his friend's telephone number. He however remembers that they are different numbers. If he dials at random, the probability that he dials correctly is

An old man while dialing a 7-digit telephone number remembers that the first four digits consist of one 1's, one 2's and two 3's. he also remembers that the fifth digit is either a 4 or 5 while has no memory of the sixt digit, he remembers that the seventh digit is 9 minus the sixth digit, maximum number of distinct trials he has to try to make sure that he dials the correct telephone number, is A. 360 B. 240 C. 216 D. none of these

An old man while dialing a 7 digit telephone humber remembcrs that the first four digits consists of one I's, one 2's and two 3's. He also remembers that the fifth digit is cither a 4 or 5 while has no memorising of the sixth digit, he remembers that the seventh digit is 9 minus the sixth digit. Maximum number of distinet trials he has to try to make sure that he dials the correct telephone number, is

Let N be the number of 6-digit numbers such that the digits of each number are all form the set {1, 2, 3, 4, 5} and any digit that appears in the number appears atleast twice. Then the number of all 6 digits is

Sam has forgotten his friend's seven-digit telephone number. He remembers the following: the first three digits are either 635 or 674, the number is odd, and the number nine appears once, what is the minimum number of trials he has to make before he can be certain to succeed?

Dialing a telephone number, a man forgot the last two digits and remembering only that they are different . He dialled the number at random. The probability of the number dialled correctly is :

Let N be the number of 6-digit numbers such that the digits of each number are all form the set {1, 2, 3, 4, 5} and any digit that appears in the number appears atleast twice. Then the last digit of N is:

Find the number of five digit numbers that can be formed using the digits 1,2,3,4,5,6,7.8,9 in which one digit appears once and two digits appear twice (e.g.41174 is one such number but 75355 is not.