Question:
The number of ordered pairs $(r, k)$ for which $6 \cdot{ }^{35} C_{r}$ $=\left(k^{2}-3\right) \cdot{ }^{36} C_{r+1}$, where $k$ is an integer, is:
Correct Option: 4
JEE Main Previous Year Jan. 7, 2020 (II)
Solution:
The number of ordered pairs $(r, k)$ for which $6 \cdot{ }^{35} C_{r}$ $=\left(k^{2}-3\right) \cdot{ }^{36} C_{r+1}$, where $k$ is an integer, is:
Correct Option: 4