GMAT question - Which of the following is a terminating decimal? - Review

Type: Problem Solving

Difficulty:

Which of the following is a terminating decimal?

A terminating decimal is one that does not go on forever.

Only factors of 10 i.e. 2 and 5 divide evenly into powers of 10 (10, 100, 1,000, 10,000 etc.).

This means that the only fractions that will terminate are those with denominators which only have prime factors which are 2 or 5.

Fraction	Denominator	Prime factorization	Only has prime factors which are 2 or 5
$mathematical expression$	7	$mathematical expression$	No (7 is the prime factor)
$mathematical expression$	33	$mathematical expression$	No (3 is one of the prime factors)
$mathematical expression$	75	$mathematical expression$	No (i3 is one of the prime factors)
$mathematical expression$	128	$mathematical expression$	Yes (2 is the only prime factor)
$mathematical expression$	312	$mathematical expression$	No (3 is one of the prime factors)

The only fraction with a denominator which has no prime factors except 2 or 5 is $mathematical expression$ and therefore D is the correct answer.

You must log in or register to add a comment.