GreenlightTestPrep wrote:
What is the remainder when \(3^{32}\) is divided by \(82\)?
A) 0
B) 1
C) 8
D) 9
E) 81
If we recognize that 82 is 1 greater than 81 (aka \(3^4\)), then we might see that 82 is a divisor of \(3^{32} - 1\)
Here's why:
\(3^{32} - 1 = (3^{16} + 1)(3^{16} - 1)\)
\(= (3^{16} + 1)(3^8 + 1)(3^8 - 1)\)
\(= (3^{16} + 1)(3^8 + 1)(3^4 - 1)(3^4 + 1)\)
\(= (3^{16} + 1)(3^8 + 1)(3^4 - 1)(82)\)
This tells us that \((3^{32} - 1)\) is a multiple of 82...
...and this means \(3^{32}\) is
1 greater than a multiple of 82, which means we'll get a remainder of
1 when we divide \(3^{32}\) by 82
Answer: B
Cheers,
Brent