[tex]\bf \cfrac{300}{~~\frac{3}{4}~~}\cfrac{pages}{hour}\implies \cfrac{\frac{300}{1}}{~~\frac{3}{4}~~}\implies \cfrac{300}{1}\cdot \cfrac{4}{3}\implies \cfrac{300}{3}\cdot \cfrac{4}{1}\implies \cfrac{100\cdot 4}{1}\implies \cfrac{400}{1}\cfrac{pages}{hour}[/tex]
400 pages in 1 hour.