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The decimal expansion of $\dfrac{257}{2^3 \cdot 5^4}$ terminates after how many decimal places?
A3
B4
C5
D7
Answer & Solution
Correct answer: B. 4
A fraction $\dfrac{p}{2^m 5^n}$ terminates after $\max(m,n)$ places. Here $m=3, n=4$, so it terminates after $\max(3,4) = 4$ places.
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