Combining rates - upstream, downstream - {time, speed} plane
This applet is a graphical workbench for the exploration of upstream-downstream problems.
The representation is in the speed vs. time plane.
Explore the solution to the following problem -
An airplane can fly 3000 miles in 6 hours if there is no wind.
It can fly that distance in 7.5 hours when it flies against the wind.
It can fly that distance in 5 hours when it flies with the wind.
How fast does the wind blow?