A dune buggy is on a straight desert road, 40 km north of Dust city. The vehicle can travel at 45 km/h off the road and 75 km/h on the road. The driver wants to go to Gulch city, 50 km east of Dust city in the shortest possible time. Determine the route he should take. The equation i can up with to solve this is: f(x) = .6(1600 + x^2)(2X) + (50 -x) ...I got the .6 by dividing 45 by 75 to get a ratio...what am I doing wrong? Please help, I have a test tomorrow and this is my last resort. Thanks. edit: the answer is 30 km east of dust city but how?