Correct answer is 432
Sum of digit at even place = x
Sum of digit at odd place = y
∵ x + y = 30, ∴x - y = 0
x - y = ± 11
Only possibility is x + y = 30 and x - y = 0
∵ x = 15, y = 15
So digit at even place is {1,5,9}, {2,4,9},{4,5,6}
Odd place is {2,3,4,6},{1,3,5,6},{1,2,3,9} respectively.
∴Total number = 3(3!-4!) = 18 x 24 = 144 x 3 = 432
