If nPr = 840 and nCr = 35, find the value of r.

Given: nPr = 840 and nCr = 35


To find: r=?


We know that:


nCr =


and


nPr =


nPr= nCr×r!


840=35×r!



r!=4!


r=4


Ans:r=4


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