"A driver makes and emergency stop and locks up the brakes of the car, which skids to a stop on dry concrete. Consider the effect of rain on this scenario. If the coefficients of kinetic friction for rubber on dry and wet concrete are μk (dry)=0.80 and μk(wet)=0.50, how much farther would the car skid (expressed in percentage of the dry-weather skid) if the concrete were instead wet?" I thought it might just be dividing dry/wet coefficients and multiplying by 100 to get the percentage. I don't think this is right, as the professor was implying there was more to solving it than that. He talked about (dry-wet)/dry to work out the answer, but it wasn't just the μ values. I feel like I missed something that should be obvious. Any help will be greatly appreciated!