What is the Correct Value of r if 9!/(9-r)! = 840?

mathdad · Mar 3, 2018

9!/(9 - r)! = 840

I found r to be 4.

Is this correct?

skeeter · Mar 3, 2018

RTCNTC said:

9!/(9 - r)! = 840

I found r to be 4.

Is this correct?

$\dfrac{9!}{(9-4)!} = \dfrac{9!}{5!} = 9 \cdot 8 \cdot 7 \cdot 6 = 3024$

there is no solution to the equation $\dfrac{9!}{(9-r)!} = 840$ for $0 \le r \le 9 \, , \, r \in \mathbb{Z}$

mathdad · Mar 4, 2018

I messed up in my calculation. Thanks.

What is the Correct Value of r if 9!/(9-r)! = 840?

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What is the Correct Value of r if 9!/(9-r)! = 840?

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