Answers

2016-03-13T06:52:10+05:30
Let a be the first term and d be the common difference of given AP then
     pth term = q
     a+(p-1)d=q_______________1
     
     qth term=p
     a+(q-1)d=p__________________2

subtracting equ 2 from 1
    (p-q)d=(q-p)
            d= -1
putting d = -1 in equ 1 , we get
       a+(p-1)-1 =q
                  a   = (p+q-1)

 nth term = a+(n-1)d
                 =(p+q-1)+(n-1)
×(-1)
                 =(p+q-n)



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