so in 1 mile there are 5280 feet, and in 1 hr there are 60 minutes, and in each minute 60 seconds, meaning in 1 hr there are 60*60 seconds, 3600 seconds.
[tex]\bf \cfrac{70 \underline{mi}}{\underline{hr}}\cdot \cfrac{5280 ft}{\underline{mi}}\cdot \cfrac{\underline{hr}}{3600 sec}\implies \cfrac{70\cdot 5280}{3600}\cfrac{ft}{sec}\implies \cfrac{308}{3}\cfrac{ft}{sec}\implies 102.\overline{6}~\frac{ft}{sec}[/tex]
