UPSC 2015 CDS I Math Paper

Let the uniform speed of the car be x km/hr.
Distance covered by the car in 8 hours =8xkm
Increased speed of the car=(x+4)km/hr
Distance covered by the car in 7 hours 30 minutes,i.e.,

15

2

hours
=

15

2

(x+4)km
∴8x=

15

2

(x+4)
16x−15x=60
⇒x=60
Distance covered by the car =8×60=480km