Question

A man made a trip of 480km in 9 hours.some part of the trip was covered at 45km/hr and the remaining at 60km/hr.find the part of the trip covered by him.

Answer 1

x is the time travelled at speed of 45kmph.the distance at 45kmph rate is 45*(4)=180km.
the distance at 60kmph is 60*(9-4)=300km.

Answer 2

total distance =480
distance covers at 45kmph =x
distance remaining =480-x
then
$\frac{x}{45} + \frac{480 - x}{60} = 9 \\ \\ solving \: we \: get \: x = 180$