Daniel is printing out copies of a presentation. it takes 3 minutes to print a color copy and 1 minute to print a black-and-white copy. he needs to print at least 6 copies and must have the copies completed in no more than 12 minutes. if the solution region represents the number of color copies and black-and-white copies that daniel can print, determine which graph represents the solution set to the system of inequalities representing this situation.

Work the information to set inequalities that represent each condition or restriction.

2) Name the variables. 

c: number of color copies
b: number of black-and-white copies

3) Model each restriction:

i) It takes 3 minutes to print a color copy and 1 minute to print a black-and-white copy.

3c + b


ii) He needs to print at least 6 copies ⇒ c + b ≥ 6


iv) And must have the copies completed in no more than 12 minutes ⇒

3c + b ≤ 12


4) Additional restrictions are c ≥ 0, and b ≥ 0 (i.e. only positive values for the number of each kind of copies are acceptable)

5) This is how you graph that:

i) 3c + b ≤ 12: draw the line 3c + b = 12 and shade the region up and to the right of the line.

ii) c + b ≥ 6: draw the line c + b = 6 and shade the region down and to the left of the line.

iii) since c ≥ 0 and b ≥ 0, the region is in the first quadrant.

iv) The final region is the intersection of the above mentioned shaded regions.

v) You can see such graph in the attached figure.