Average Speed

[anubhavgulati]

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.

[svd.kumar]

Average Speed = Total distance / Total Time (Always).

If you found any problem please give the problem also.

Thanks,
SVD

[anubhavgulati]

Can some one please let me know. Thanks.

[tpr-becky]

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.