Answer:
Ox>5
x is less than 5
means nothing more than 5 but anything less than 5
6d -11/2 = 2d -13/2
Subtract 2d from both sides
6d -11/2 - 2d = 2d -13/2 - 2d
Simplifying
4d -11/2 = -13/2
Add 11/2 to both sides
4d -11/2 + 11/2 = -13/2 + 11/2
Simplifying
4d = -2/2
4d = -1
Divide both sides by 4
4d/4 = -1/4
Simplifying
d = - 1/4
Formula is:
Number of reams per case x number of cases
11 x 12 = 132 reams