Chebyshevs Theorom, can u figure this out?

math is fun!

If the average is 111.6 and if the SD is 2.8 and we are looking for the percent between the intervals of 90.6 and 125.6, then what is the percent? Notice that this isn't a normal question because from the mean there is a difference of (-)21 on the left side (90.6-111.6) and 14 on the right side (125.6-111.6)? It's not an 'even'/ balanced interval, so how do u do it? any one have any clues?