Question

the average speed of a car is 20km/hr more than the average speed of a bus,.if the car takes 4 hours less than the bus to cover a Distance of 300km. find the average speed of the car and the bus

Answer 1

Answer:

Step-by-step explanation:

Let the average speed of the bus be  ykm/hr

the time taken by the bus to complete the journey be  t hr

Therefore according to the given data the average speed of car is given by y+20

And the time taken by the car to complete the journey is given by t-4

Speed×time=distance

Applying the above formula

we get

(y+20)(t-4)=300 for the car

and y×t=300 for the bus

y×t - 4y + 20t -80 =300

20t-4y=80

We are having two equation and two variables substituting the value of y=300÷t in equation 2

20t - 1200÷t=80

20t^2 -1200=80t

20t^2-80t-1200=0

2t^2 - 8t -120=0

t^2- 4t -60=0

t^2 -10t+6t-60=0

t(t-10) +6(t-10)=0

t=10hr

y=300÷10

 = 30km/hr

Speed of bus= 30km/hr

Speed of car =50km/hr