Three lights go on together first changes every 5 sec second every 6sec third every 8 sec when is the next time they go on together

Each of the walls of a room with square dimensions has been built with two pieces of sheetrock, a smaller one and a larger one. the length of all the smaller ones is the same and is stored in the variable small. similarly, the length of all the larger ones is the same and is stored in the variable large. write a single expression whose value is the total area of this room. do not use any method invocations.

Julius sold five times as many computers as sam sold last year. in total, they sold 78 computers. how many computers did julius sell?

X/y + 4y/x divided by x/y - 2y/x explain as in depth as you can how you simplfied the fractions. i don't know where to start on this : /