Question

After 4 minutes of reading, Aaron was on page 14 of his book. After 8 minutes he was on page 20. Which equation models the page number, y in terms of minutes x?

A. y=-8x+1.5
B. y=1.5x+8
C. y=8x+1.5
D. y=-1.5x+8

Answer 1

Given:

After 4 minutes of reading, Aaron was on page 14 of his book.

After 8 minutes he was on page 20.

To find:

The equation that models the page number, y in terms of minutes x.

Explanation:

Let y be the page number after x minutes of reading.

After 4 minutes of reading, Aaron was on page 14 of his book. So, the line must be passes through (4,14).

After 8 minutes he was on page 20. So, the line must be passes through (8,20).

The equation of line which passes through two points is

`y-y_1=(y_2-y_1)/(x_2-x_1)(x-x_1)`

The required line passes through (4,14) and (8,20), so the equation is

`y-14=(20-14)/(8-4)(x-4)`

`y-14=(6)/(4)(x-4)`

`y-14=1.5(x-4)`

`y-14=1.5x-6`

Add 14 on both sides.

`y-14+14=1.5x-6+14`

`y=1.5x+8`

Therefore, the correct option is B.