• # question_answer If A.M. between ${{p}^{th}}$ and ${{q}^{th}}$ terms of an A. P. be equal to the A.M. between ${{r}^{th}}$ and ${{s}^{th}}$ term of the A. P., then $p+q$ is equal to A) $r+s$ B) $\frac{r-s}{r+s}$ C) $\frac{r+s}{r-s}$ D) $r+s+1$

 $\frac{{{t}_{P}}+{{t}_{q}}}{2}=\frac{{{t}_{r}}+{{t}_{s}}}{2}=a+(p-1)\,d+a+(q-1)\,d=$$a+(r-1)\,d+a+(s-1)\,d$ $\therefore$      $p+q=r+s.$