Question

the data in the table compares x, the number of pages in a chapter, to y, the amount of time, in minutes, spent reading. the function $y = 0.86x - 0.09$ models the data in the table.
time spent reading

pages in a chapter	time spent reading (minutes)
12	11
5	4
26	22
20	17

which is the best prediction for the number of pages in a chapter that takes 18 minutes to read?
15
17
19
21

Explanation:

Step1: Substitute \( y = 18 \) into the function

We have the function \( y=0.86x - 0.09 \). Substitute \( y = 18 \) into it: \( 18=0.86x-0.09 \).

Step2: Solve for \( x \)

Add \( 0.09 \) to both sides of the equation: \( 18 + 0.09=0.86x-0.09 + 0.09 \), which simplifies to \( 18.09 = 0.86x \).
Then divide both sides by \( 0.86 \): \( x=\frac{18.09}{0.86}\approx21 \).

Answer:

21