Find the number of different words which can be formed using all the letters of the word ‘HISTORY’.
Every way of arranging letters of the HISTORY will give us a word.
Therefore total number of ways to permutate letters H, I, S, T, O, R, Y, in a row
= Total number of words that can be formed using all letters together =
Find the number of rectangles that you can find on a chessboard.
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.
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.
Find the largest such that
Find the largest integer n for which 35! Is divisible by 3n.
The number of natural numbers which are smaller than 2 × 108 and which can be written by means of the digits and 2 is ………..
Find the exponent of 2 in 50!?
Find the number of zeroes in 100!
A city has 12 gates. In how many ways can a person enter the city through one gate and come out through a different gate?
In how many ways 5 different red balls, 3 different black balls and 2 different white balls can be arranged along a row?