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Question

243! In the trailing Zeros, let us know.

This question was previously asked in
RPF SI 2018 Question Paper PDF (10-Jan-2019) (Shift 1)
The correct answer is

58

The number of trailing zeros in n! equals the number of times 5 appears as a factor, found by \(\left\lfloor \frac{n}{5} \right\rfloor + \left\lfloor \frac{n}{25} \right\rfloor + \left\lfloor \frac{n}{125} \right\rfloor + \dots\).

\(\left\lfloor \frac{243}{5} \right\rfloor = 48\), \(\left\lfloor \frac{243}{25} \right\rfloor = 9\), \(\left\lfloor \frac{243}{125} \right\rfloor = 1\), and \(\frac{243}{625}\) is less than 1.

Total = 48 + 9 + 1 = 58.

Hence, 243! has 58 trailing zeros.

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Important Questions from Multiples and Factors

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