This is the original situation of the problem where there are three planes, AAL-12, DAL-88, and UAL-74, all need to get to the destination without crashing and in the right time frame.
Here is the simulator paused at one minute where the AAL-12's speed had been changed to 480 knots and the DAl-88's speed was changed to 540 knots.
After the pause at one minute, all the planes were reset back to 600 knots for the rest of the flight. All three planes made it to the MOD destination successfully without crashing and on time.
Simulator Problem 4-4
In this problem, there are four planes - AAL-12, SWA-23, DAL-88, and UAL-74 that all need to get to the MOD on time and safely.
The SWA-88 plane is set to 540 knots and the UAL-74 is set to 480 knots for one minute. The AAl-12 plane had its route change to a more direct path.
After one minute, all planes were brought back to 600 knots and they all reached the destination safely and on time.