Question: The number of ordered pairs $(\mathrm{r}, \mathrm{k})$ for which
$6 \cdot{ }^{35} \mathrm{C}_{\mathrm{r}}=\left(\mathrm{k}^{2}-3\right) \cdot{ }^{36} \mathrm{C}_{\mathrm{r}+1}$, where $\mathrm{k}$ is an integer, is :
Correct Option: , 3
Solution:
