A motor car starts with a speed of 50km/hr with its speed increasing every 2hours by 20kmph. In how many hours will it cover 510kms?  Choices:  A) 12 hr  B) 10hr  C) 9hr  D) 11hr  E) 8hr
Distance covered in first 2hours = 50*2= 
<gadget id="calculator">50*2</gadget>
<output>100</output>
100km   Distance covered in next 2hours= 70*2= 
<gadget id="calculator">70*2</gadget>
<output>140</output>
140km   remaining distance= 510- (100+140)= 
<gadget id="calculator">510- (100+140)</gadget>
<output>270</output>
270km   speed in the fifth hour= 90km/hr   total time to cover 270km = 270/90= 
<gadget id="calculator">270/90</gadget>
<output>3</output>
3 hr   total time taken= 4+(3) = 12hours   correct option is 12 hr
<result>A</result>
A motor car starts with a speed of 50km/hr with its speed increasing every 2hours by 20kmph. In how many hours will it cover 510kms?