CMA Foundation · Fundamentals of Business Mathematics and Statistics · Permutation and Combinations
How many zeros does 25! end with?
25! ends with 6 zeros. Each trailing zero needs one factor of 10, and factors of 2 are plentiful, so count factors of 5. There are 5 multiples of 5 up to 25, plus one more from 25 itself, giving 6 in total.
- A4
- B5
- C6Correct
- D7
Explanation
Trailing zeros equal the number of factors of 5. Count: floor(25/5) = 5 plus floor(25/25) = 1, total 6. Option 5 misses the extra factor from 25 = 5², which contributes a second 5.
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