Write an equation and solve:
1. A stock inventory of an item was 65 on Monday morning. At the close of business on Friday, the inventory level was 18. How many were sold during the week?
2. A person ran at 880 ft./min for the first 10 minutes of the 3 mile race before slowing their pace to finish the race with a total time of 20 minutes. What was their pace (IN FEET PER MINUTE) for the second part of the race.
3. Jeffrey biked to the store at 12 mi./hr. but took his time on the way home, going 8 mi./hr. If it took him 20 min. to get to the store, how many minutes did it take him to get back?