A bus travels at a certain average speed for a distance of 75 km and then travels a distance of 90 km at an average speed of 10 km/h more than the first speed. If it takes 3 hours to complete the total journey, find its first speed?
Let x be the initial speed of the bus.
We know that
`75 (x+10)+ 90x= 3x(x+10)`
`(x+5)=0 or (x-50)=0`
`x=-5 or x=50`
Speed cannot be negative and hence first speed of the train is 50 km/hour.