1: A forum goes downstream from Pier A to Pier B, and it needs 8 to disappear. When it returns, it needs 12 to disappear. Given that the current speed is 3 km/h, find the voyage between two piers!

144

S=(8T+24)

S=( 12T-36)

2. The aircraft carrier sails from west to east at a speed of 20 kilometers per hour, and the aircraft takes off from the aircraft carrier and sails westward at a speed of 800 kilometers per hour to perform tasks. If the plane can fly in space for at most 3 hours and then disappear, then it should start to return to the aircraft carrier within a few hours after take-off. (accurate to 0.0 1 hour)

800/(800-20)*3=3.07