Chapter 2 - Section 2.2 - Graphs of Functions - Exercise Set - Page 124: 43

$ a.\quad $ $81$ In 2010 (30 years after 1980), the wage gap was $81\%.$ $ b.\quad $ $G(30)$ underestimates the actual data by $ 2\%$

$ a.\quad$ $G(30)=-0.01(30^{2})+30+60=81$ In 2010 (30 years after 1980), the wage gap was $81\%.$ $ b.\quad $ The bar graph gives the value to be $ 83\%$, when x=30 (in the year 2010). So, with $ 81\%$, the model $G(x)$ underestimates the actual data by $ 2\%$