Question

Alfred is practicing typing. The first time he tested himself, he could type 27 words per minute. After practicing for a week, he could type 29 words per minute. After two weeks he could type 31 words per minute. Based on this pattern, predict how fast Alfred will be able to type after four weeks of practice.

Answer 1

So, from looking at the increase of wpm per week, we can see it is increasing at a rate of 2 wpm per week (wpm is words per minute).
Initially, without practice, he was able to type 27 words per minute.
From then on, it started to increase at 2wpm.
In terms of x's and y's, since the rate, we know m; it is 2; that's the rate at which his typing speed is increasing.
Since, before week 1, (week 0), he was able to type 27 wpm, this tell us the y-intercept; when x=0.
Plug those values for y=mx+b:
y=2x+27

Answer 2

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