Question

A young equestrian loved to ride her horse all day long, dreaming of the day she would ride in the Kentucky Derby. One day in early April, she left home at 10:00 am and rode her stallion at a nice, steady 10 miles per hour away from her house. At noon a call came in from the Derby saying she was in! Her father immediately jumped on his scooter to try and track her down and tell her the good news. Riding at a breezy 15 miles per hour, at what time will her father catch up to her?

Answer 1

The first step is:
- determine how far from the house is young equestrian at noon. 
2 x 10 = 20 miles
15 t = 20 + 10 t
15 t - 10 t = 20
5 t = 20
t = 20 : 5
t = 4 hours
Answer: at 4:00 PM.