Early in the twentieth century, most schools had compulsory education laws requiring students to attend until the age of sixteen. This age was then raised to eighteen since people thought not enough kids were being trained for the workforce. Now it is simply that you have to graduate high school.
They went somewhere where they can farm and grow food
Your answer for this would be 6 years, the american revolution ended on 1783 and the ratification of the Constitution was on 1789
The Gupta civilization and the Maya civilization were similar in that both built temples complexes and developed the concept of zero.
Hope that helps your assignment