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How many zeros are there at the end of the product $5 \times 10 \times 15 \times 20$ × … × 100?

Competition practiceNumber System, HCF & LCM

A24
B20
C22
D18

Step-by-Step Solution

The product is

5^{20} \times 20!

. Fives are plentiful (24), but 2s come only from 20!:

10 + 5 + 2 + 1 = 18

. So 18 zeros.

Answer: D) 18

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