Question

The interstate speed limit is 70 mph. If there are 5280 feet in a mile, how fast are you going in feet per second?

Answer 1

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.

`\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}~(ft)/(sec)`