Rounding Question

[flysoohigh63]

This problem is taken from p.15 of MGMAT Guide 1:

If x is the decimal 8.1d5, with d as an unknown digit, and x rounded to the nearest tenth is equal to 8.1, which digits could not be the value of d?

The answer given is:
In order for x to be 8.1 when rounding to the nearest tenth, the right-digit-neighbor, d, must be less than 5. Therefore, d cannot be 5,6,7,8 or 9.

But what if x=8.145?
Can we round it as 8.145 = 8.15 (by the rounding rule) and then 8.15=8.2 (applying rounding rule again)?
Logically 8.145 is closer to 8.1 than to 8.2, but if we apply rounding rules, we get 8.145=8.2
Therefore in the first problem d cannot be 4 as well.

Can you please explain where is a flaw in my reasoning?

[RonPurewal]

"Rounded to the nearest tenth" means ... rounded to the nearest tenth.

It doesn't mean rounded to the nearest hundredth and THEN rounded to the nearest tenth (as you're doing).

[flysoohigh63]

Got it! Thanks!

[RonPurewal]

You're welcome.