A car traveling at 65mph on a poor, wetpavement has a braking efficiency of 90%. The brakes were applied 200feet before hitting an obstaclein the road. The road is uphillfor 90feet and then is levelfor the remainder of the way. The car had a maximum coefficient of road adhesion in the slopedportion of the poor, wet roadway and started sliding as soon as it started going level, which reduced its coefficient of road adhesion to 0.3. Assuming that the car struck the obstacleat 37mph, what was the grade of the hill? Assume practical stopping distance equation applies.