`10p_r = 720`

If ""^(10)P_(r) = 720, find r.

IF ""^(10)p _r = 5040 then r=

If .^(n)P_(r) = 720 and .^(n)C_(r) = 120 , then find r. .

If .^(n)P_(r) = 720 . " If " .^(n)C_(r) = 120 " find " n , r

If .^(n)P_(r) = 720 and .^(n)C_(r) = 120 , then find r. = (5 xx 4 xx 3)/(3 xx 2 xx1) xx (4xx 3 xx 2)/(3 xx 2xx1) = 10 xx 4 = 40 .

Find n and r if. (a)^nP_r = 720 and ^nC_(n-r) = 120 (b) ^nC_(r-1) : ^nC_r : ^nC_(r+1) = 20 : 35 : 42

Find r if : "^10P_r= 2^9P_r .

If ^np_r=720 and ^nC_r=120 find r