Test 8 Section 3 #13

You’re translating from words into math here. Key words to note: “at a constant rate” means you’re dealing with something linear, that has a slope. And “*decreased* at a constant rate” means you’re looking for a negative slope.

Because the function is a function of *t*, years are your *x*-variable and and millions of barrels is your *y*-variable. Calculate the slope from the numbers the question provides: 4 million barrels in 2000 and 1.9 million barrels in 2013.

Note that while no answer choice has that slope in that *exact* form, choice C is equivalent. .

Because all the answer choices have the same *y*-intercept of 4, you need not think much about it, but it does make sense given the question. There were 4 million barrels in 2000 and *t* represents years after 2000, so *t* = 0 when the *y*-variable is 4.