<p>For number 15 I got C, why is the answer A? And for number 18, why is option 3 correct?
Thanks.</p>
<p>Not sure what you’re saying, the answer to number 15 IS C.</p>
<p>Sorry, I meant Number 15 Page 399. My bad.</p>
<p>p399 #15:</p>
<p>Height at 6 yrs= 45 inches
Height at 12 yrs= 60 inches</p>
<p>So to find the percent increase you do:
45x=60
x=60/45
x=1.333</p>
<p>Since it asks you for the “percent greater” It would be 1.333=133.3%=33.3 % greater, or C.
Number 15, Page 399 is C. You got it right. :)</p>
<p>p. 400 # 18:</p>
<p>f(a) is the line y=f(x). Because the shaded region is below the line at all times, b must be less (or below) or equal to the line. I know that explanation was a little confusing, but its the best I can do.</p>
<p>Haha exactly, the answer to 15 on page 399 is C!</p>
<p>As for 18, simply plotting the points will help you validate III. A more clear solution is available here: [Khan</a> Academy](<a href=“Khan Academy”>Khan Academy).</p>