Question

car travel first 30 km with a
uniform speed of 60 Km h and the
next 30 km with an uniform speed
of 40 Km h calcutate
1) the total time of journey 2)the average speed of car​

Answer 1

Given :

A car travel first 30 km with a uniform speed of 60 km/h and the next 30 km with an uniform speed of 40 km/h

To find :

(i) Total time of journey

(ii) The average speed of the car

Solution :

Formula to calculate time :-

• Time = Distance ÷ Speed

Time taken to travel first 30 km :-

we have,

• Distance = 30 km
• Speed = 60 km/h

Substituting the given values :-

→ Time = 30/60

→ Time = 3/6

→ Time = 1/2

Time taken to travel first 30 km = 1/2 hour

Time taken to travel next 30 km :-

we have,

• Distance = 30 km
• Speed = 40 km/h

Substituting the given values :-

→ Time = 30/40

→ Time = 3/4

Time taken to travel next 30 km = 3/4 hours

Total time for the journey = Time taken to travel first 30 km + Time taken to travel next 30 km

→ Total time = 1/2 + 3/4

→ Total time = (2 + 3)/4

→ Total time = 5/4

Therefore,

• Total time taken for the journey = 5/4 hours

Average speed of the car :-

Formula to calculate average speed :-

• Average speed = Total distance travelled ÷ Total time taken

we have,

→ Total distance = 30 + 30 = 60 km/h

→ Total time = 5/4 hours

Substituting the given values :-

→ Average speed = 60 ÷ 5/4

→ Average speed = (60 × 4)/5

→ Average speed = 12 × 4

→ Average speed = 48

Therefore,

• The average speed of the car = 48 km/h