2,442 runners who took part in a 10km race had an average time of 1 hr and 11 minutes.The standard deviation was 12 minutes.Using Chebysheff's theorem,determineat least how many runnershad a running time between53 minutes and 89 minutes?

I need to find K first, using mean-k(sd)=LL, then 1-1/k^2. There might be other ways, but this is what we are encouraged to do. I'm still getting the occasional wrong answer on these, might just be my algebra operations, so please show those operations as much as possible.

Using practice questions to review for test, and submitting over and over for practice. Our system generates new numbers every time you submit.