To find the rate in miles per hour, divide the miles by the hours.
(1 1/2 miles)/(3/5 hour) =
= 3/2 miles * (5/3 hour)
= 5/2 mph
= 2 1/2 mph
Her walking rate is 2 1/2 mph.
(4 1/2 miles) / ( 2 1/2 mph) =
= 9/2 miles / (5/2 mph)
= 9/2 * 2/5 hours
= 9/5 hours
= 1 4/5 hours
From 9:00 a.m. to 11 a.m., she has 2 hours, but she only needs 1 4/5 hours to walk, so she will make it to work on time.
