Bunuel wrote:
When a truck travels at 60 miles per hour, it uses 30 percent more gasoline to travel any distance than it does when it travels at 50 miles per hour. The truck can travel 20 miles on a gallon of gas if it is traveling at 50 miles per hour. The truck has only 10 gallons of gas and is 160 miles from its destination. It takes 20 minutes for the truck to stop for gas. How long will it take the truck to reach its final destination if it is driven at 60 miles per hour?
(A) 160 minutes
(B) 180 minutes
(C) 190 minutes
(D) 192 minutes
(E) 195 minutes
(A) 160 minutes
(B) 180 minutes
(C) 190 minutes
(D) 192 minutes
(E) 195 minutes
Speed = 50 miles/Hr ; Gasoline usage = 1 gallon/20 miles
Speed = 60 miles/Hr ; Gasoline usage = 1.3 gallon/20 miles
Total Stock of Gasoline = 10 gallons
Till 120 miles; D travelled = 120 miles; Speed = 60 miles/Hr; Gasoline Used = 7.8 gallons (2.2 left) ; time taken = 2 hrs
Till 140 miles; D travelled = 140 miles; Speed = 60 miles/Hr; Gasoline Used = 9.1 gallons (0.9) ; time taken = 140 mins
Stop for Gasoline = 20 mins ; time taken = 160 mins
Till 160 miles; D travelled = 160 miles; Speed = 60 miles/Hr; time taken = 160+20 mins = 180 mins (20 mins to travel 20 miles)
B