<p>How do you reason 1 + 0.07(20 - t) out of $1.00 for any time up to and including 20 minutes and $0.07 per minute thereafter?</p>
<p>I'm just slightly confused.</p>
<p>Wouldn’t it be (t-20)?</p>
<p>On the online explanations they say it’s (20-t), where t is a positive integer greater than 20.</p>
<p>Analogous is correct, i was looking at the explanations and that’s what it says.</p>
<p>it is a typo. it should be (t-20). </p>
<p>f(t) = 1 + 0.07(t-20)</p>
<p>f(20) = 1
f(21) = 1.07
f(22) = 1.14
f(23) = 1.21</p>