Terminating Decimal- Mgmat cat 4 DS

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Terminating Decimal- Mgmat cat 4 DS

by khurram » Sun Apr 13, 2008 9:42 am
What is terminating decimal does it mean that if a=1.1111 and b=1.1111
a/b=1 all decimals cancel out?

Thanks in advance
Khurram


If a, b, c, d and e are integers and p = 2a3b and q = 2c3d5e, is p

q a terminating decimal?




(1) a > c

(2) b > d
Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
Both statements TOGETHER are sufficient, but NEITHER one ALONE is sufficient.
EACH statement ALONE is sufficient.
Statements (1) and (2) TOGETHER are NOT sufficient.

For fraction p/q to be a terminating decimal, the numerator must be an integer and the denominator must be an integer that can be expressed in the form of 2x5y where x and y are nonnegative integers. (Any integer divided by a power of 2 or 5 will result in a terminating decimal.)

The numerator p, 2a3b, is definitely an integer since a and b are defined as integers in the question.

The denominator q, 2c3d5e, could be rewritten in the form of 2x5y if we could somehow eliminate the expression 3d. This could happen if the power of 3 in the numerator (b) is greater than the power of 3 in the denominator (d), thereby canceling out the expression 3d. Thus, we could rephrase this question as, is b > d?

(1) INSUFFICIENT. This does not answer the rephrased question "is b > d"? The denominator q is not in the form of 2x5y so we cannot determine whether or not p/q will be a terminating decimal.

(2) SUFFICIENT. This answers the question "is b > d?"

The correct answer is B.
Source: — Data Sufficiency |

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by AleksandrM » Wed Apr 16, 2008 9:42 am
Yes, I am curious to see an elaboration on this one.