What were the clues?
Let x be that missing digit. Then the Bank Account Number looks like, 3170x4847.
Now 9 x First Digit + 8 x Second Digit + 7 x Third Digit.......must be divisible by 11.
That is 27 + 8 + 49 + 0 + 5x + 16 + 24 + 8 + 7 = 139 + 5x must be divisible by 11.
The only value of x as a digit the satisfies above is 3. With that, total sum 154 is divisible by 11.
Hence, the Account Number must be, 317034847.
