Bluebook SAT Test Linear Functions 5

Question 1

A truck travels at a constant speed. After 2 hours it has traveled 110 miles, and after 5 hours it has traveled 275 miles. How many miles per hour is the truck traveling?

Accepted Answer

55 mph

Answer

Rate = (275 − 110)/(5 − 2) = 165/3 = 55 mph.

Question 2

Which line is perpendicular to y = (2/3)x + 1?

Accepted Answer

y = −(3/2)x + 5

Answer

Perpendicular slopes are negative reciprocals; the negative reciprocal of 2/3 is −3/2, giving y = −(3/2)x + 5.

Question 3

A linear function f satisfies f(0) = −6 and f(4) = 10. What is f(6)?

Accepted Answer

18

Answer

Slope = (10 − (−6))/(4 − 0) = 16/4 = 4; f(x) = 4x − 6; f(6) = 24 − 6 = 18.

Question 4

In the function P(t) = 1200 − 40t, P represents the number of gallons of water in a pool and t represents time in hours. What does −40 represent?

Accepted Answer

The rate at which water drains (40 gallons per hour)

Answer

The coefficient of t (slope) = −40 represents the rate of change: water decreases by 40 gallons each hour.

Question 5

If the equation of a line is written as 6x − 2y = 8, what is the slope of the line?

Accepted Answer

3

Answer

Rewrite in slope-intercept form: −2y = −6x + 8 → y = 3x − 4, so the slope is 3.

Bluebook SAT Practice Test

Bluebook SAT Practice Test

Bluebook SAT Test Linear Functions 5