7) The half-life of a drug in the bloodstream is 9 hours. By what factor does the concentration of the drug decrease in 13 hours? A) 0.05 B) 2.72 C) 0.14 D) 0.37 8) Poaching is causing a population of elephants to decline by 5% per year. Use the approximate half-life formula to determine the fraction that remains in 59 years if there are 8661 elephants today. A) 8243 elephants B) 467 elephants C) 4829 elephants D) 18,250 elephants 9) A linear function has a constant rate of change and a curved graph. A) False B) true 10) The rate of change is equal to the slope of the graph. A) False B) True 11) In the algebraic equation of a line, the y-intercept is denoted by the letter . A) x B) y C) m D) b 12) The the rate of change, the steeper the slope. A) greater B) more independent C) more dependent D) smaller Write an equation for the linear function and use it to answer the given question. 13) Normaltown High Schoolʹs pool record for the 100-yard freestyle was 46.7 in 1990. Assume that the record falls at a constant rate of 0.07 second per year. What does the model predict for the record in 2017? A) R = 46.7 - 0.07t; 44.81 seconds B) R = 46.7t - 0.07; 1260.83 seconds C) R = 46.7 + 0.07t; 48.59 seconds D) R = 46.7t + 0.07; 1260.97 seconds 14) In 1995 the United States recovered 20% of its municipal solid wastes through recycling, up from 17% in 1990. Let P represent the percentage recycled and t the number of years since 1990. Based on these two data points, create a linear equation for the function that describes how P varies as a function of time. A) P = -0.6t + 7 B) P = 0.6t + 17 C) P = 0.3t - 17 D) P = 0.6t + 24