Car Travels : Find the average speed of the car.
Q / āĻĒā§ā§°āĻļā§āĻ¨ : A car travels four consecutive distances of 3 km each at speeds of 10, 20, 30 and 60 km/h respectively. Find the average speed of the car.
(āĻāĻāĻ¨ āĻāĻžāĻĄāĻŧā§āĻ¯āĻŧā§ 3 āĻāĻŋāĻŽāĻŋ āĻā§ āĻāĻžā§°āĻŋāĻāĻž āĻāĻā§ā§°āĻžāĻšā§ āĻĻā§ā§°āĻ¤ā§āĻŦ āĻā§ā§°āĻŽā§ 10, 20, 30 āĻā§°ā§ 60 āĻāĻŋāĻŽāĻŋ/āĻāĻŖā§āĻāĻž āĻŦā§āĻā§ā§°ā§ āĻ āĻ¤āĻŋāĻā§ā§°āĻŽ āĻā§°ā§āĨ¤ āĻāĻžāĻĄāĻŧā§āĻāĻ¨ā§° āĻāĻĄāĻŧ āĻŦā§āĻ āĻ¨āĻŋā§°ā§āĻŖāĻ¯āĻŧ āĻā§°āĻžāĨ¤)
Options / āĻŦāĻŋāĻāĻ˛ā§āĻĒ: A) 10 km/h B) 20 km/h C) 30 km/h D) 60 km/h
Solution / āĻ¸āĻŽāĻžāĻ§āĻžāĻ¨
Total Distance / āĻŽā§āĻ āĻĻā§ā§°āĻ¤ā§āĻŦ
= 3 + 3 + 3 + 3 = 12 km / 12 āĻāĻŋāĻŽāĻŋ
Total Time / āĻŽā§āĻ āĻ¸āĻŽāĻ¯āĻŧ
= 3/10 + 3/20 + 3/30 + 3/60
= 18/60 + 9/60 + 6/60 + 3/60
= 36/60
= 3/5 hour / 3/5 āĻāĻŖā§āĻāĻž
Now,
Average Speed = Total Distance ÷ Total Time (āĻāĻĄāĻŧ āĻŦā§āĻ = āĻŽā§āĻ āĻĻā§ā§°āĻ¤ā§āĻŦ ÷ āĻŽā§āĻ āĻ¸āĻŽāĻ¯āĻŧ)
= 12 ÷ 3/5
= 12 × 5/3
= 20 km/h
Ans / āĻāĻ¤ā§āĻ¤ā§°: B) 20 km/h / 20 āĻāĻŋāĻŽāĻŋ/āĻāĻŖā§āĻāĻž
Formula / āĻ¸ā§āĻ¤ā§ā§°: Average Speed = Total Distance / Total Time (āĻāĻĄāĻŧ āĻŦā§āĻ = āĻŽā§āĻ āĻĻā§ā§°āĻ¤ā§āĻŦ / āĻŽā§āĻ āĻ¸āĻŽāĻ¯āĻŧ)
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