Explanation:

33 = 11 x 3
Number x * y * x
Divisible by 11 = (x + y + x) - (x + x) = y
Hence, y being a single digit number must
be divisible by 11 or else be zero

.For divisibility by 3, number must be
divisible by 3
x + x + 0 + x + x
= 4x
For 3,6 &9, we will get ‘4x’ as multiple of 3
Hence, number can be one of below three:
33033, 66066 & 99099
Hence, answer is 3.