A bag contains green marbles and red marbles, 59 in total. The number of green marbles is 1 less than 4 times the number of red marbles. How many green marbles are there?

How can you know if the person or organization providing the information has the credentials and knowledge to speak on this topic? one clue is the type of web site it is--the domain name ".org" tells you that this site is run by a nonprofit organization.

Howard is designing a chair swing ride. the swing ropes are 5 meters long, and in full swing they tilt in an angle of 29° outside chairs to be 2.75 m above the ground in full swing.

Some of the first computer games were created in the early 1970s by college students experimenting after hours to see what the were capable of doing.