With an uniform speed, a car covers a distance in 8 hours. had the speed been increased by 4 km/hr, the same distance could have been covered in 7 hr and 30 min. What is the distance covered ?

Answer: Option B

Let the speed of car be x km/hr
Distance = Speed × Time
Distance = 8x km
According to the question,
$$\begin{array}{rl}& \Rightarrow \left(x+4\right)\times 7.5=8x\\ & \Rightarrow 7.5x+30=8x\\ & \Rightarrow 8x-7.5x=30\\ & \Rightarrow 0.5x=30\\ & \Rightarrow x=\frac{30}{0.5}=60\text{ km/hr}\end{array}$$
Required distance :
= 8 × 60
= 480 km