If the hundreds digit is twice the tens digit then the hundreds digit must be even.
The hundreds digit then can't be less than 6 because half of 4 is 2 and 2+4=6 which then wouldn't enable a third number to add up to 17.
Using 6 as the hundreds digit:
Therefore the tens digit must be three and the last 8.
The reverse then is 836, 836-638=198, so this is not the number.
The tens digit is 4
And the last digit must be 5
The reverse then is 548,
Numbers are 845 and 548.