To reach his potential, Jack wants to increase his running speed by 2/3 mile/hour. It he increases his speed at the rate of 1/8 mile/hour each month, how long will it take him to reach his potential?
2/3 ÷ 1/8 = 2/3 * 8/1 = 16/3
or, keeping track of the units, you want to convert mi/hr to months, so
2/3 mi/hr ÷ (1/8 mi/hr)/1mo = 16/3 mo