There are 100 runners, each given a distinct bib labeled 1 to 100. What is the most number of runners that we could arrange in a circle, such that the product of the numbers on the bibs of any 2 neighboring runners, is less than 1000?

7 answers

it is greater than 61
it is less than 80
it is less than 70
it is less than 65
is it 49
no tis not 49
The Answer is 61.