A certain population is modeled by the function P (t) = StartFraction 50,000 Over 1 + 4 e Superscript negative 0.5 t Baseline EndFraction. How long will it take for the population to reach 30,000 organisms? approximately 0.4 years
approximately 0.8 years
approximately 3.6 years
approximately 8.1 years

Astudent draws two parabolas on graph paper. both parabolas cross the x-axis at (–4, 0) and (6, 0). the y-intercept of the first parabola is (0, –12). the y-intercept of the second parabola is (0, –24). what is the positive difference between the a values for the two functions that describe the parabolas? write your answer as a decimal rounded to the nearest tenth