A truck driver starts with the speed of 70 kmph with the truck driver decreasing speed every two hours by 10 kmph. The truck driver's speed does not drop below 50 kmph. In how many hours will it take the truck driver to travel 500 kms? Choose the correct choice from the following answers:
A) 480 minutes B) 492 minutes C) 504 minutes D) 528 minutes E) 540 minutes
Distance covered in first two hours = 70 Ã— 2 = 140 km   Distance covered in next two hours = 60 Ã— 2 = 120 km   Distance covered in next two hours = 50 Ã— 2 = 100 km   Distance covered in next two hours = 50 Ã— 2 = 100 km   Distance covered in first eight hours    140 + 120 + 100 + 100= 
<gadget id="calculator"> 140 + 120 + 100 + 100</gadget>
<output>460</output>
460 km   Remaining distance= 500 â€“ 460 = 40 km.   Now, this distance will be covered at the speed of 50 km/hr.   âˆ´ Time taken = 40â„50 = 4â„5 hour.   Total time= 8 + 4â„5 = 8 4â„5 hour   Answer 528 minutes
<result>D</result>
A truck driver starts with the speed of 70 kmph with the truck driver decreasing speed every two hours by 10 kmph. The truck driver's speed does not drop below 50 kmph. In how many hours will it take the truck driver to travel 500 kms?