Children start to gain control over their attention beginning in preschool. This control is related to a growth spurt in the brain's lobe.

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?

Idon’t quite understand this problem

Which is an example of an exothermic process?