decimal rounding

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decimal rounding

by cubicle_bound_misfit » Wed Sep 17, 2008 5:33 am
In the number 1.4ab5, a and b represent single positive digits. If x = 1.4ab5, what is the value of 10 – x?

(1) If x is rounded to the nearest hundredth, then 10 – x = 8.56.

(2) If x is rounded to the nearest thousandth, then 10 – x = 8.564.


Please explain.

thanks.
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by 4meonly » Wed Sep 17, 2008 9:27 am
I think B


what is the value of 10 – 1.4ab5?
(1)
If x is rounded to the nearest hundredth, then 10 – x = 8.56.
10 – x = 8.56 => x=1,44
we don't know anything about b
if b>=5 a is 3
if b<5 a is 4
INSUFF

(2)
If x is rounded to the nearest thousandth, then 10 – x = 8.564.
10 – x = 8.564 => x=1,436
we know that x=1.4ab5
rounded to the nearest thousandth .... we get 6, but we have 5 at the end, so b was 5
hundredth will remain the same - 3
so x=1.4355
10-1.4355 = .... you don't need it
SUFF

Answer B

What is OA?