Answer
(a) 2009.
(b) 2009 to 2011.
Work Step by Step
(a) Given $W=0.33x+33.1$, to exceed $34\%$, let $W\ge34$, we have $0.33x+33.1\ge34$ which gives $x\ge2.7$. Thus it needs at least 2 years or until 2009.
(b) let $33.9\le W\le 34.5$, we have $33.9\le 0.33x+33.1\le 34.5$ or $0.8\le 0.33x\le 1.4$ which gives $2.4\le x\le 4.2$ meaning years 2009 to 2011.
