Answer: 53.5 miles/hour
Step-by-step explanation:
(21 2/5 miles)/(2/5 hour) =
(21 2/5 miles)/(2/5 hour) =
(105/5 + 2/5 miles) or (107/5) miles
(107/5 miles)/(2/5 hour)
(107/5) miles/(2/5 hour)
(107/5) /(2/5 ) miles/hour
(107/5) *(5/2 ) miles/hour
(535/10) miles/hour
53.5 miles/hour
