The Washington Post Co. expects the profits from its embattled education division to plummet this year, as the federal government probes Kaplan Higher Education’s recruitment practices and education quality. Although revenue increased $1.8 billion in 2010, it dropped 3 percent in the last three months of the year compared with the fourth quarter of 2009 as enrollment slowed amid the scrutiny. The for-profit chain laid off 770 employees, or 5 percent of its work force, in December because of the declining enrollment.