Solve the problem.
-Persons taking a 30-hour review course to prepare for a standardized exam average a score of 620 on that exam. Persons taking a 70-hour review course average a score of 804. Find a linear equation which fits this data.
A) y = 4.14x - 486
B) y = 4.14x + 486
C) y = 4.6x + 482
D) y = -4.6x + 482

Question

Quizplus · Accepted Answer

We can use the two given data points (30, 620) and (70, 804) to find the slope of the line:

slope = (804 - 620) / (70 - 30) = 4.6

Then, we can use either of the two points and the slope to find the y-intercept. Using (30, 620):

y = mx + b 
620 = 4.6(30) + b 
620 = 138 + b 
b = 482

So the equation of the line is y = 4.6x + 482, which matches choice C. Let x be the number of hours of review course and y be the exam score. We have two points (30, 620) and (70, 804). Using the two-point form of a linear equation, we get:

y - 620 = (804 - 620)/(70 - 30) * (x - 30)

Simplifying the expression, we get:

y - 620 = 4.84*(x - 30)

y = 4.84x - 14.8 + 620

y = 4.84x + 605.2

Comparing this equation with the given options, we see that the closest match is option C, y = 4.6x + 482. Therefore, the answer is C.

Solve the Problem. -Persons Taking a 30-Hour Review Course to Prepare for a Prepare