For example , say Person # 1 sends a letter through the mail , while Person # 2 sends letters through email .
Both of these costs are corollated with one another in that to decrease one , you must increase the other .
Say Person # 1 sends a letter through the mail , while Person # 2 sends letters through email .
Both of these costs are corollated with one another in that to decrease one , you must increase the other .