Physics Help - Wave Problem?

A sand scorpion can detect the motion of a nearby beetle (its prey) by the waves the motion sends along the sand surface. The waves are of two types: transverse waves traveling at vt = 57 m/s and longitudinal waves traveling at vl = 155 m/s . If a sudden motion sends out such waves, a scorpion can tell the distance of the beetle from the difference Δt in the arrival times of the waves at its leg nearest the beetle. If Δt = 6.2 ms, what is the beetle's distance (in cm)?