Question

A vehicle travels 250 km with a speed of 60kmh 1 and returns to the start point with a speed
of 80 kmh 1. Calculate average speed of vehicle.
(Express your answer upto two decimal places)​

Answer 1

Given:-

• Distance covered ,D1 = 250 km

• Speed ,S1 = 60km/h

• Distance covered ,D2 = 250 km (because it returns to the starting Point )

• Speed ,S2 = 80km/h

To Find:-

• Average speed ,Av.Speed

Solution:-

Firstly we calculate the time taken by Vehicle in each case.

• Time = Distance/Speed

In 1st case

→ t1 = D1/S1

→ t1 = 250/60

→ t1 = 4.16 s

And Now calculating time in 2nd Case

→ t2 = D2/S2

→ t2 = 250/80

→ t2 = 3.12 s

And , We know that Average Speed is defined as the total distance covered by total time taken.

• Av.Speed = Total Distance/Total time

Substitute the value we get

→ Av.S = D1+D2/t1+t2

→ Av.S = 250+250/4.12+3.12

→ Av.S = 500/7.24

→ Av.S = 69.06 m/s

Therefore, the average speed of the vehicle is 69.06 m/s.

Answer 2

Solution

Given,

• D1 = 250km
• D2 = 250Km
• S1=60km/hr
• S2= 80km/hr

To find

• average speed

we have to calculate the time taken by the vehicle in each case .

Now,

$\blue{time = \frac{distance}{speed} }$

In first case ;

$\green{ = > t1 = \frac{d1}{s1} }$

$= > t1 = \frac{250}{60}$

$\green{ = > t1 = 4.16s}$

now calculating the time in the second case ;

$\green{t2 = \frac{d2}{s2} }$

$= > t2 = \frac{250}{80} \\ = > \green{3.12s}$

now I have to find the average speed .

We know that average speed

$\bold{ = \frac{total \: distance}{total \: time} }$

now putting the value we get ;

$= > \bold{av = \frac{d1 + d2}{s1 + s2} }$

$= > \frac{250 + 250}{4.12 + 3.12}$

$= > \frac{500}{7.24} \\ = > 69.06 \: m/ s \:$

The average speed is 69•06m/s .