Question

Please answer
The average speed of a train is 320/x.
A car takes 2.5 hours longer than a train to travel between the same places. The average speed of the train is 80km greater than the average speed of the car.
For an equation that simplifies to,
2xsquare+5x-20​
​

Answer 1

Step-by-step explanation:

Let the speed of express train be x km/h

Let the speed of passenger train be y km/h

x=y+10..........(i)

Time is defined as the ratio of distance to speed.

Time of express train is less than passenger train by 2 h

x

400

+2=

y

400

...........(ii)

Substituting value of x from (i) in (ii), we get:

y+10

400

+2=

y

400

Rearranging terms, we get:

y

2

+10y−2000=0

y

2

+50y−40y−2000=0

(y+50)(y−40)=0

y=−50,40

Speed cannot be negative.

y=40

From equation (i), x=y+10=50

Hence,

average speed of express train is 50 km/h

average speed of passenger train is 40 km/h