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If \(x\) is a prime number greater than \(3,\) what is the remainder when \(x^2\) is divided by \(8?\)

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Re: If \(x\) is a prime number greater than \(3,\) what is the remainder when \(x^2\) is divided by \(8?\)

by deloitte247 » Sat Sep 12, 2020 11:51 pm
Prime numbers greater than 3 are 5, 7, 11, ...
$$So,\ if\ x=5,\ then\ \frac{x^2}{8}=\frac{5^2}{8}=\frac{25}{8}=3\ remainder1$$
$$So,\ if\ x=7,\ then\ \frac{x^2}{8}=\frac{7^2}{8}=\frac{49}{8}=6\ remainder1$$
$$So,\ if\ x=11,\ then\ \frac{x^2}{8}=\frac{11^2}{8}=\frac{121}{8}=15\ remainder1$$
In all cases, remainder = 1

Answer = option B
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