consider 7 digit no. x1x2….x7 where x1,x2,….x7 ?2 having property x4 is greatest digit and digit towards the left and right of x4 are in decreasing order. Total no. of such nos in which all digits are distinct is a)9C7*6C3 b) 9C6* 5C3 c) 10C7*6C3 d) 9C2*6C3

Vatsal Koradia , 15 Years ago

Grade 11