Question
If ${ }^{n} P_{r}=504$ and ${ }^{n} C_{r},=84$, find the values of $n$ and $r$.
Step 1
We know that ${ }^{n} C_{r}$ is equal to ${ }^{n} P_{r}$ divided by $r!$. So, we can write the equation as follows: \[84 = \frac{504}{r!}\] Show more…
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