a person drove on a highway first 5km at a speed of 60km/h ,the second 5km at a speed of 85km/h , third 5km at a speed of 92km/h and last 5km of his journey,the speed was 8okm/h.Use suitable average to find average speed of the journey of 20km.
(60+85+92+80)/4 = ?
To find the average speed of the entire journey, you need to calculate the total distance covered and the total time taken.
In this case, the person traveled 5 km at a speed of 60 km/h, then another 5 km at a speed of 85 km/h, then 5 km at a speed of 92 km/h, and finally, the last 5 km at a speed of 80 km/h.
First, let's calculate the total distance covered:
Total Distance = 5 km + 5 km + 5 km + 5 km = 20 km
Now, let's calculate the total time taken:
Time taken = Distance / Speed
For the first 5 km:
Time taken = 5 km / 60 km/h = 1/12 hour
For the second 5 km:
Time taken = 5 km / 85 km/h = 1/17.0 hour (rounded to one decimal place)
For the third 5 km:
Time taken = 5 km / 92 km/h = 1/18.4 hour (rounded to one decimal place)
For the last 5 km:
Time taken = 5 km / 80 km/h = 1/16.0 hour (rounded to one decimal place)
Now, let's calculate the total time taken for the entire journey:
Total Time = (1/12 hour) + (1/17.0 hour) + (1/18.4 hour) + (1/16.0 hour)
To calculate the average speed, divide the total distance by the total time:
Average Speed = Total Distance / Total Time
Substituting the values:
Average Speed = 20 km / (1/12 + 1/17.0 + 1/18.4 + 1/16.0)
Now, perform the calculations to find the average speed.