## Thinking Mathematically (6th Edition)

$\{1980, 1990\}$
$A=\{x|x$ was a year in which more than $34\%$ were very happy$\}$ $B=\{x|x$ was a year in which fewer than $14\%$ were not too happy$\}$ $A\cap B=?$ From the graph we can see that: $A=\{1980, 1990\}$ $B=\{1980, 1990, 2000\}$ $A\cap B=\{1980, 1990\}$