Question

Please send solution as much as possible ​

Answer 1

Step-by-step explanation:

nPr=720

n!/(n-r)!=720___(1)

nCr=120

n!/(n-r)!r!=120____(2)

(1)/(2)==>r!=720/120

r!=6

r=6

put r=6 in (1)

n!/(n-6)!=720

n(n-1)(n-2)(n-3)(n-4)(n-5)(n-6)!/(n-6)!=720

n(n-1)(n-2)(n-3)(n-4)(n-5)=720