If an object travels 400 feet in 4 seconds, what is the object's approximate speed in miles per hour? (Note: 1 mile = 5280 feet) Select the correct option
A) 68  B) 54  C) 87  D) 96  E) 15

Rationale: "1 mile = 5280 feet = > 1 feet = 1 / 5280 miles if the object travels 400 feet in 4 sec then it travels 400 / 4 * 60 * 60 feet in 1 hour ( 1 hr = 60 min * 60 sec ) = 3600 * 100 feet in 1 hour = 360000 feet in 1 hr = 360000 / 5280 miles in 1 hour = 36000 / 528 miles / hr ~ 68 miles / hr answer - a"
Answer: A