Typo in New Blue Book

[Vernacular]

<p>Number 13 on page 641. It's a blatant one.</p>

[jubilant]

<p>… The missing = sign?</p>

[fignewton]

<p>Wonder if there’s a find-the-typo prize, that’s a nasty one! It should read:</p>

<p>c(x) = (600x - 200)/x + k, where x <= 100.</p>