PermutationandCombination
Question 1 
P = Q  k
 
P = Q + k  
P = Q
 
P = Q +2 k

Question 1 Explanation:
P=1+3+5+7+...+(2k1)
=(21)+(41)+(61)+(81)+...+(2k1)
=(2+4+6+8+...+2k)+(1+1+1+k times)
=Q(1+1+...+k times)
=Qk
Question 2 
The number of substrings (of all lengths inclusive) that can be formed from a character string of length n is
n  
n^{2}  
Question 2 Explanation:
No. of substrings of length
n = 1
(n1) = 2
(n2) = 3
So, Total = n(n+1)/2
n = 1
(n1) = 2
(n2) = 3
So, Total = n(n+1)/2
There are 2 questions to complete.