Which statement is correct about the decimal expansion of \(\frac{13}{40}\)?

Correct answer: It is a terminating decimal because, in lowest form, the denominator has only 2 and 5 as prime factors.

\(\frac{13}{40}\) is already in lowest form, and \(40=2^3\times5\). A rational number has a terminating decimal expansion when the prime factors of its denominator in lowest form are only 2 and/or 5. Therefore, \(\frac{13}{40}=0.325\). Option B is incorrect because 40 has no prime factor other than 2 and 5, so the decimal does not recur. Exam tip: first reduce the fraction to lowest terms, then factorise its denominator.