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QUESTION 5 (NOV.24TH)

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by dmateer25 » Mon Nov 24, 2008 4:11 pm
Here is a quote from Ian on how to determine if a fraction is terminating.
I'll try to state the rule as unambiguously as possible. If you need to know whether a fraction represents a terminating decimal:

1) Reduce the fraction completely;
2) Prime factorize the denominator;
3) Look at this prime factorization, and ignore the exponents. If there is a prime besides 2 or 5 in the denominator, the fraction represents a recurring (non-terminating) decimal. If the only primes in the denominator are 2, 5, or both, the fraction represents a terminating decimal.

So 9/125, 3/32, 7/80 and 3/30 are all terminating decimals (when you look at 3/30, you must reduce the fraction first, of course), while 7/121, 5/33, 7/60 and 19/99 all represent recurring decimals.
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by niraj_a » Tue Nov 25, 2008 3:30 pm
correcto. Ian's method is the fastest to do this and is mentioned in the new MGMAT books as well.
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