RTD question

[Duffett.matt]

Reiko drove from point A to point B at a constant speed, and then returned to A along the same route at a different constant speed. Did Reiko travel from A to B at a speed greater than 40 miles per hour?

(1) Reiko's average speed for the entire round trip, excluding the time spent at point B, was 80 miles per hour.

(2) It took Reiko 20 more minutes to drive from A to B than to make the return trip.


I set up my chart but I just don't know where to start with this question.

[tim]

You're off to a fine start - setting up a chart is your first step! Continue by filling in what you can - you don't know the speeds, so give them variables. You don't know the distance, so you can give that a different variable, keeping in mind both distances are the same. Now you can fill in the time column (remember it's distance divided by rate), and then you can add up the times and distances for your total row, finishing by dividing the total distance by the total time to get the total rate. Using statement 1, you can try a few numbers to quickly determine that there are no numbers less than or equal to 40 you can plug in for either rate that will allow you to get a total rate of 80. This is certainly not the most efficient approach, but it will get you there. I'll leave it to you to try statement 2 using a similar approach.

[RonPurewal]

please search the forum before posting. thanks.

https://www.manhattanprep.com/gmat/foru ... 16415.html

[RonPurewal]

(... and, if you have any remaining questions after reading the entire thread linked above, please post them on that thread. thanks.)