Find the Constant of Variation K $N$ Varies Jointly As $t$ And $p$

Multiple Choice

Find the constant of variation k.
- $N$ varies jointly as $t$ and $p$ . When $t$ is 6 and $p$ is $3 , N$ is 36 .

A) $k = 72$
B) $k = 648$
C) $k = 2$
D) $k = 18$