Yahoo Answers is shutting down on May 4th, 2021 (Eastern Time) and beginning April 20th, 2021 (Eastern Time) the Yahoo Answers website will be in read-only mode. There will be no changes to other Yahoo properties or services, or your Yahoo account. You can find more information about the Yahoo Answers shutdown and how to download your data on this help page.
Trending News
A motorist travels 80 km at 100 km/h, and 50 km at 75 km/h. What is the average speed for the trip?
I know that Average Speed = Total Distance / Time but I do not understand how to get the time out of the kph and the total distance.
2 Answers
- FiremanLv 79 years agoFavorite Answer
By time(t) = distance(s)/speed(v)
=>t1 = 80/100 = 0.8 hour & t2 = 50/75 = 0.67 hr
=>By v(avg) = (s1+s2)/(t1+t2) = (80+50)/(0.8+0.67) = 88.64 km/hr
- 9 years ago
D1 = distance traveled with 100Km/h = 80Km
D2 = distance traveled with 75Km/h = 50Km
t1 = time spent for 80Km trip
t2 = time spent for 50Km trip
And, by the formula, Speed = Distance/Time
S1 = D1/t1 => t1 = D1/S1
S2 = D2/t2 => t2 = D2/S2
Total average speed = Total Distance/Total time = {(D1+D2)s1*s2}/(D1*S2+D2*S1)
