Q. 85.0( 2 Votes )

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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