if 6 pr = 360 and if 6 cr = 15 , find r ?
solution : npr = ncr � r ! 6 pr = 15 * r ! 360 = 15 * r ! r ! = 360 / 15 = 24 r ! = 4 * 3 * 2 * 1 = > r ! = 4 ! therefore , r = 4 . answer : option c
divide(divide(360, 15), 6)