In the number 1.4*a**b*5, *a* and *b* represent single positive digits. If *x *= 1.4*ab*5, 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.

SPOILER: OA: B. This tells us that *x* rounded to the nearest thousandth must be 1.436. This means, that *a*, the hundredths digit, is equal to 3. As for*b*, the thousandths digit, we know that it is followed by a 5 (the ten-thousandths digit); therefore, if *x *is rounded to the nearest thousandth, *b *must rounded UP. Since *b *is rounded UP to 6, then we know that *b* must be equal to 5 ..... this is the official explanation,however, Iam not sure if we can say that b was **rounded up**. The original number could be 1.4355 OR 1.4365.

The rounding off rule that I am using is this ....

** In rounding off numbers, if the first figure dropped is 5, and all the figures following the five are zero ***or* if there are no figures after the 5, then the last figure kept should be unchanged if that last figure is even.

** In rounding off numbers, if the first figure dropped is 5, and all the figures following the five are zero ***or* if there are no figures after the 5, then the last figure kept should be increased by 1 if that last figure is odd.