if nPr = 720 and nCr=120 find r
Hello Shivani, nPr = n (n-1) (n-2) ....{n - (r-1)} = 720
But nCr = n (n-1) (n-2) ...{n - (r-1)} / 1.2.3...r = 120
Hence 1.2.3.4.. r = 6
Hence r = 3
As r = 3 then n = 10
Verification: 10P3 = 10 * 9 * 8 = 720
And 10 C 3 = 10* 9 * 8 / 1. 2. 3 = 120 VERIFIED
But nCr = n (n-1) (n-2) ...{n - (r-1)} / 1.2.3...r = 120
Hence 1.2.3.4.. r = 6
Hence r = 3
As r = 3 then n = 10
Verification: 10P3 = 10 * 9 * 8 = 720
And 10 C 3 = 10* 9 * 8 / 1. 2. 3 = 120 VERIFIED
