**Question:**

Let $T_{\mathrm{r}}$ be the rth term of an A.P. whose first term is a and common difference is $d$. If for some positive integers $m, n, m \neq n, T_{m}=\frac{1}{n}$ and $T_{n}=\frac{1}{m}$, then $a-d$ equals

Correct Option: 4

JEE Main Previous Year 2004

**Solution:**