Divisibility rules of 8?

Number Theory Level 3

Which of the following is not divisible by 8?

8^{80}

6^{60}

2^{20}

4^{40}

None of these

1 solution

Oliver Papillo
Jan 3, 2018

$8 = 2^3$

As all of the bases of these terms are divisible by $2$ , and all the exponents are greater than $3$ , all of the terms are divisible by $8$ .