Which type of satellite has the shortest orbital life?

When many atoms are split in a chain reaction, a large explosion occurs. this is an example of what type of energy conservation

From center station, a train departs every 30 minutes on the fast line and a train departs every 50 minutes on the state line. if two trains depart from center station at 8: 00 a.m., one on each of the two lines, what is the next time that two trains, one on each line, will depart at the same time?

If y gets smaller as x gets bigger and y have an relationship?