Grades 11-12 Video Solutions 2021-video 2021 11-12/8

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Video Summary

The problem is to find how many three-digit numbers can be formed using the digits 1, 3, and 5 that are divisible by 3. A number is divisible by 3 if the sum of its digits is divisible by 3. With the given digits, the combinations that satisfy this condition are 135, 555, 333, and 111. The number 135 can be arranged in six different ways due to its unique digits (3 factorial), while the others have only one arrangement each. Adding these, there are a total of nine such numbers. The answer is 9.

Keywords

three-digit numbers

divisible by 3

digit combinations

unique arrangements

mathematical problem