This applet is a workbench for the exploration of all upstream-downstream problems.[br][br]It opens with the solution to the following problem - [br]An airplane can fly 3000 miles in 6 hours if there is no wind.[br]It can fly that distance in 7.5 hours when it flies against the wind.[br]It can fly that distance in 5 hours when it flies with the wind.[br][br]How fast does the wind blow?

- GOING FURTHER[br][br]1. Use this applet to generate several different upstream-downstream problems. [br][br]2. Compare this applet to "Combining rates I - Joe & Sam paint a wall.[br]How is it similar? different?