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OlympiadHardNumber Theory7–9

What is the smallest positive integer divisible by $15$ whose digits are all $0$ or $1$ ?

Qual é o menor inteiro positivo divisível por $15$ cujos algarismos são todos $0$ ou $1$ ?

Answer options

Solution

Step 1 of 3

1.Divisible by $15$ means divisible by $5$ and by $3$ . With digits only $0$ and $1$ , the last digit must be $0$ .