What is the difference between iterative and sequential?

The average cost of one year at a private college in 2012-2013 is $43,289. the average grant aid received by a student at a private college in 2012-2013 is $15,680.   what is the average student contribution for one year at a private college in 2012-2013?

In which part of a professional email should you try to be brief, but highly descriptive?

Me with this program in c++ ! computers represent color by combining sub-colors red, green, and blue (rgb). each sub-color's value can range from 0 to 255. thus (255, 0, 0) is bright red. (130, 0, 130) is a medium purple. (0, 0, 0) is black, (255, 255, 255) is white, and (40, 40, 40) is a dark gray. (130, 50, 130) is a faded purple, due to the (50, 50, 50) gray part. (in other word, equal amounts of red, green, blue yield gray).given values for red, green, and blue, remove the gray part. ex: if the input is 130 50 130, the output is: 80 0 80. thus, find the smallest value, and then subtract it from all three values, thus removing the gray.