Got this question on my first GRE attempt and it caught me off guard. Anyone know how I’d go about solving this? Probably possible without calculator.

Thanks!

Got this question on my first GRE attempt and it caught me off guard. Anyone know how I’d go about solving this? Probably possible without calculator.

Thanks!

Is your question right ? Because the largest divisor of a number is the number itself. 3^100-3^97 gives some weird number. Maybe ur question was largest prime divisor which is 13 in this case

Hi there,

you might be absolutely right and I just didn’t remember the question correctly.

How did you get to 13 for the largest prime divisor? And how would you go about solving terms like 3^100-3^97 in general? Thank you!

3^100 - 3^97

3^97(3^3 - 1)

3^97(27-1)

3^97 * 26

13*2 = 26 . hence the largest prime divisor is 13

2 Likes