Permutations an...

There are 9 chairs in a room on which 6 persons are to be seated, out of which one is guest with one specific chair. In how many ways they can sit

The number of ways in which 10 persons can go in two boats so that there may be 5 on each boat, supposing that two particular persons will not go in the same boat

The total number of natural numbers of six digits that can be made with digits 1,2,3,4, if all digits are to appear in the same number at least once, is

All possible two factors products are formed from numbers 1,2,3,4,...,200. The number of factors out of the total obtained which are multiples of 5 is

A father with 8 children takes them 3 at a time to the Zoological gardens, as often as he can without taking the same 3 children together more than once. The number of times he will go to the garden is

The product r consecutive integers is divisible by

The total number of +ve integral solutions (zero included) of x + y + z + w = 20, without restrictions is

If the (n + 1) numbers a, b, c, d,........ be all different and each of them a prime number, then the number of different factors (other than 1) of a^m.b. c.d..... is

Given that n is odd, the number of ways in which three numbers in A.P. can be selected from 1, 2, 3,....., n is

The tens digit of 1! + 2! + 3! +..... + 49! is