we have to make n with k integers.k integers will have to be choosen from k ranges.Every range has a minimum value and a maximum value.In how many ways we can make n
according to the conditions.For example,k=4,n=10
and the ranges are :
1 1
2 2
3 3
4 4
we can make n in only one way.Another...
Given N positive integers, not necessarily distinct, how many ways you can take 4 integers from the N numbers such that their GCD is 1. One of my friend told me that he can determine the number of ways with inclusion-exclusion principle and found the result 195 for given N=10 and the positive...