The median household income divides the households into two groups: the half whose income is less than or equal to the median, and the half whose income is greater than the median. The median household income in the United States grew from about $30,000 in 1990 to about $48,000 in 2006. (Source: U.S. Census Bureau)
(A) If I represents the median household income and t represents the number of years since 1990, write a linear equation that expresses I in terms of t.
(B) Use this equation to estimate median household income in the year 2030.