Question

ncr = 136 , n=17 , find r?​

Answer 1

Step-by-step explanation:

ncr = 136

cr =136/7

r =136r/7

Answer 2

Answer:

$\large\boxed{\sf{r=2}}$

Step-by-step explanation:

According to Question;

$^n{c}_r = 136 \\ \\ = > \frac{n!}{r!(n - r)!} = 136 \\ \\ = > \frac{17!}{r!(17 - r)!} = 136 \\ \\ = > \frac{17 \times 16 \times15 !}{r!(17 - r)!} = 17 \times 8 \\ \\ = > \frac{2 \times 15!}{r!(17 - r)!} = 1 \\ \\ = > r!(17 - r) != 2 \times 15! \\ \\ = > r!(17 - r)! = 2! \times 15! \\ \\ = > r!(17 - r)! = 2!(17 - 2)!$

On Comparing both the sides, we get

$\bold{r = 2}$