Rounding decimals

[manjus_mailme]

The question is

7.5XY9
What digit does X represent if each of X and Y are single digits in the above decimal?
1. If the decimal is rounded to the nearest hundredth, the result is 7.55.
2. If the decimal is rounded to the nearest tenth, the result is 7.5.

The answer is BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is
sufficient.The explanation given is

Statement 1 says that the result of rounding the decimal to the nearest hundredth is 7.55. No
information is given about the thousandths place so it is impossible to determine if the last digit of
7.55 was originally 5 or 4. Statement 1 alone is insufficient to answer the question. The answer
must be B, C, or E.
Statement 2 says that the result of rounding the decimal to the nearest tenth is 7.5. Notice that
according to our rounding rules, this statement implies that the digit in the hundredths spot in the
original decimal, was less than 5. There are 5 different digits less than 5 (including 0), and
Statement 2 alone gives us no way to determine which of those is the actual value of the
hundredths digit. Statement 2 alone is also NOT sufficient to answer the question.
Since the digit represented by the "X must be 4, the statements together are sufficient to answer
the question

According to me, if X must be 4 then how does statement 1 states that the decimal rounded to the nearest hundredth, the result is 7.55.This seems controversial.Is my understanding correct?

[kstv]

This has been discussed before. Just put a search you may get some inputs

7.5XY9
What digit does X represent if each of X and Y are single digits in the above decimal?
1. If the decimal is rounded to the nearest hundredth, the result is 7.55.
2. If the decimal is rounded to the nearest tenth, the result is 7.5.
1.) Rounded to the nearest hundreth is two places right of the decimal point.
so 7.5XY9 *100 = 75X.Y9 if Y >= 5 you add 1 to X
if X is 5 it also possible that X is originally 5 and Y is < 5 or X was 4 and Y >= 5
So Insuff.
2.) here we know X < 5 , otherwise rounnding to tenth will be 7.6 not 7.5
no clue of Y Still Insuff
But you are wiser in knowing X < 5 , take that knowlegde to 1. So here in 1.) u are certain Y >= 5 and one is added to X to make 7.54Y9 where Y >=5 7.55

[dream700]

from statement 2 we get x < 5... (we ll later see that x = 4)

now the no. is 7.54Y9...

now statement 1 says "If the decimal is rounded to the nearest hundredth, the result is 7.55."

so Y should be equal to 9.

thus when we round of to nearest hundred, 1 is carry forwarded and we get the no. to be 7.55

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