Hi All,
In this prompt, we're asked for the TENTHS digit of X? This question asks for the digit that is to the IMMEDIATE RIGHT of the decimal point.
Fact 1: The hundredths digit of X is 5
This tells us NOTHING about the tenths digit - that digit could be any integer from 0 to 9, inclusive.
eg.
X = _.05
X = _.15
X = _.25
...
X = _.95
Fact 1 is INSUFFICIENT
Fact 2: Number X, rounded to the nearest tenth, is 54.5
This Fact discusses ROUNDING. If the hundredths digit is 0-4, then we 'round down'; if the hundredths digit is 5-9, then we 'round up.'
eg.
IF.....
X = 54.49, then we would 'round up' to 54.5
X = 54.53, then we would 'round down' to 54.5
Thus, the tenths digit could be 4 or 5.
Fact 2 is INSUFFICIENT
Combined, we know...
The hundredths digit of X is 5
Number X, rounded to the nearest tenth, is 54.5
Since the hundredths digit is 5, that means that we would have to round UP to get to 54.5. Thus, X could only be 54.45
Combined, SUFFICIENT
Final Answer:
GMAT assassins aren't born, they're made,
Rich
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