Explanation: 
Another Explanation (5):
nPr : nCr = k : 1 🤔
আমরা জানি, nPr = \(\frac{n!}{(n-r)!}\) এবং nCr = \(\frac{n!}{r!(n-r)!}\) 😎
তাহলে, \(\frac{^{n}P_{r}}{^{n}C_{r}} = \frac{\frac{n!}{(n-r)!}}{\frac{n!}{r!(n-r)!}}\) 🧐
= \(\frac{n!}{(n-r)!} \times \frac{r!(n-r)!}{n!}\) 🥰
= r! 🤩
যেহেতু, nPr : nCr = k : 1 🥳
সুতরাং, k = r! 🎉