With a uniform speed a car covers a distance in 8 hours. Were the speed increased by 4 km/hr the same distance could be covered in 7 1⁄2 hours. What is the distance covered?  Choices
A) 640 km  B) 480 km  C) 420 km  D) Cannot be determined  E) None of these
Here D⁄7.5 - D⁄8 = 4   (where D is the distance in km)   ⇒ 0.5 D = 4 × 8 × 7.5   ⇒ D = 2 × 4 × 8 × 7.5 = 480 km   Answer 480 km
<result>B</result>
With a uniform speed a car covers a distance in 8 hours. Were the speed increased by 4 km/hr the same distance could be covered in 7 1⁄2 hours. What is the distance covered?