A survey approximates the number of Americans that are age 65 and older and projects that by the year 2050 approximately 82 4 million Americans will be at least 65 The bar graph shows the estimated number of Americans with projected figures for the year 2020 and beyond A graphing calculator screen displays an exponential function that models the U S population age 65 and over y in millions x years after 1899 Use this information to solve a d below Click the icon to view the bar graph a Explain why an exponential function was used to model the population data A An exponential function was used because exponential functions are always more accurate than linear functions OB An exponential function was used because the data in the bar graph is increasing more and more rapidly OC An exponential function was used because population is always modeled using exponential functions OD An exponential function was used because there are too many data points to use a linear function b Use the graphing calculator screen to express the model in function notation with numbers rounded to three decimal places f x 0 c According to the model in part b how many Americans age 65 and over were there in 2010 Use a graphing calculator million Type an integer or a decimal rounded to one decimal place as needed Does this rounded number overestimate or underestimate the 2010 population displayed by the bar graph By how much Choose the correct answer below and fill in the answer box to complete your choice Type an integer or decimal rounded to one decimal place as needed OA The rounded number overestimates the 2010 population by OB The rounded number underestimates the 2010 population by million million I d According to the model in part b how many Americans age 65 and over will there be in 2020 ExpReg y a b x a 3 500502606 b 1 022918115