Correct Option - D
Let the digits of the number be a and b.
10a + b = 0.6x
10b + a = 1.6x
Subtracting one from the other, we get
9b - 9a = x or x = 9( b-a)
x should be a multiple of 9.
0.6 = 3/5
10a + b = 3x/5, this implies that x should also be a multiple of 5.
Or, x should be a multiple of 45
x should be equal to 45, ab = 27, ba = 72