Question : The force (in pound-force) needed to keep a car from skidding on a curve varies directly with the weight of the car (in pounds) and the square of its speed (in miles per hour [mph]) and inversely with the radius (in feet) of the curve. Suppose 6125 pound-force is required to keep a 2750 pound car, travelling at a speed of 35 mph, from skidding on a curve of radius 550 feet. How much pound-force is then required to keep a 3600-pound car, travelling at a speed of 50 mph, from skidding on a curve of radius 750 feet?

Option 1: 11960

Option 2: 12150

Option 3: 12240

Option 4: 12000

Question : By driving the car at an average speed of 40 km per hour, I reach my destination in 7 hours. With what speed I can reach the same destination in 5 hours?

Option 1: 50 km per hour

Option 2: 56 km per hour

Option 3: 55 km per hour

Option 4: 65 km per hour