Question

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 785. Find a linear function which fits this data.

Answer 1

y = 4.125x + 496.25

Explanation:

Set the data up as points. Then deal with the points.

Givens

(30,620)

(70,785)

y2 = 785

y1 = 620

x2 = 70

x1 = 30

Formula

Slope = (y2 - y1) / (x2 - x1)

Solution

Slope = (785 - 620)/(70 - 30)

Slope = 165 / 40

Slope = 4.125

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Now you need the y intercept. Either one of the two given points will give you that.

y = 620

x = 30

m = 4.125

y = mx + b

620 = 4.125*30 + b

620 = 123.75 + b

620 - 123.75 + b

b = 496.25