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1. Due to improved technology and public-service campaigns, the number of collis

ID: 3038185 • Letter: 1

Question

1. Due to improved technology and public-service campaigns, the number of collisions at highway-railroad crossings per year as declined since 1985. Let n be the number of collisions (in thousands) for the year that is t years since 1980.Use the linear model y = -0.211x + 8.06 to estimate the number of collisions in 1994.

2. Suppose a college bookstore sells 784 copies of a new (not used) textbook in 2008. Each year from 2008 to 2010, the new-textbook sales are half of the previous year’s sales (due to used-textbook sales). Let f = g(x) be the sales of copies of new textbook in the year that is x years since 2008. Find an equation of g.

3. Find an equation of the line that passes through (-2, 14) and (-6, 8).

SHOW WORKING

Explanation / Answer

y = 0.211x + 8.06

number of collisions in 1994

plug x = 14

y = 0.211(14) + 8.06

y = 11.014

number of collisions in 1994 are 11 thousand approx