Question

in an AP if mth term is n ad nth term is m, then its rth term is
(i) m+n
(ii) m+n-r
(iii) m+r
(iv) none

Answer 1

Answer:

m+n is the correct answer

Answer 2

Answer:

let a is the 1st term and d is the common difference if the AP series

so, mth term is a+(m-1).d=n

again,nth term is a+(n-1).d=m

subtracting, (m-1).d-(n-1).d=n-m

=> d(m-1-n+1)=n-m

=> d(m-n)= -(m-n)

=> d= -(m-n)/(m-n)= -1

putting the value of d= -1

a+(n-1).d=m

=> a+(n-1).(-1)=m

=> a-n+1=m

=> a=m+n-1

so, r th term

a+(r-1).d

=m+n-1+(r-1)(-1)

=m+n-1-r+1

=m+n-r

so (ii) is the right answer