Leisure The average amount of money spent on books and magazines per household in the United States can be modeled by the function r (t) = -0.2837t2 + 5.5468t +136.68. Here, r(t) is in dollars and is the number of years since 1985. The model is based on data for the years 1985-2000. In what year(s) was the average expenditure per household for books and magazines greater than $160?
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