Average Speed

This topic has expert replies
Senior | Next Rank: 100 Posts
Posts: 47
Joined: Sun May 29, 2011 5:28 am
Thanked: 1 times
Followed by:1 members

Average Speed

by anubhavgulati » Wed Oct 05, 2011 6:34 am
Hi,

I am Confused while solving Average Speed Problems, which method need to imply when....?

1. Average Speed = 2* First Speed * Second Speed / (First Speed+Second Speed)
2. Average Speed = Total Distance / Total Time
3. Average Speed = Distance/Time

Can someone please let me know. Thanks.
Source: — Problem Solving |

Junior | Next Rank: 30 Posts
Posts: 27
Joined: Tue Sep 21, 2010 7:38 am
Thanked: 4 times

by svd.kumar » Wed Oct 05, 2011 6:43 am
Average Speed = Total distance / Total Time (Always).

If you found any problem please give the problem also.

Thanks,
SVD

Senior | Next Rank: 100 Posts
Posts: 47
Joined: Sun May 29, 2011 5:28 am
Thanked: 1 times
Followed by:1 members

by anubhavgulati » Wed Oct 05, 2011 11:31 am
Can some one please let me know. Thanks.

User avatar
GMAT Instructor
Posts: 509
Joined: Wed Apr 21, 2010 1:08 pm
Location: Irvine, CA
Thanked: 199 times
Followed by:85 members
GMAT Score:750

by tpr-becky » Wed Oct 05, 2011 8:12 pm
Not sure when the first formula would be appropriate, I've never used that formula on GMAT problems.

The only real difference between the second and the third is the word total -they are the same problem. However, you would be more apt to use the second formula if you had more than one segment in a trip, or more than one thing moving. Then you would have to find each distance and each time and add them up.

The third formula would be more reasonable if you only had one trip segment or moving thing. The formula is really the same - because if you only have one thing then the distance is the same as the total distance.
Becky
Master GMAT Instructor
The Princeton Review
Irvine, CA