Zoom, here is my explanation:
For statement one, x can be either .4545, .4546, .4547, .4548, .4549 OR .4551, .4552, .4553, .4554. These are the only values that will give us .455. Thus, (1) is not sufficient.
Statement two tells us nothing because we have no idea what the preceding numbers are before the thousandths digit.
If we combine both statements together, refer back to the possible values of x from statement 1. The only value with "5" in the thousandth's place is .4545. Thus, the result when x is rounded to the nearest hundredth is .46.
What is the result when x is rounded to the nearest hundredth ?
1 - when x is rounded to the nearest thousandth the result is 0.455
2 - the thousandths digit of x is 5