Mary is chopping up some old furniture to make firewood. Chairs make 6 sticks of wood, tables make 9 sticks of wood, and stools make 2 sticks of wood. Mary needs to burn 5 sticks of wood per hour to stay warm. If Mary chops up 18 chairs, 6 tables and 4 stools, how many hours can she keep warm? Let's be accurate as possible.
First find the total sticks from the chairs: 6 sticks / chair * 18 chairs = 108 sticks. Then find the total sticks from the tables: 9 sticks / table * 6 tables = 54 sticks. Then find the total sticks from the stools: 2 sticks / table * 4 stools = 8 sticks. Then add up the total number of sticks she gets: 108 sticks + 54 sticks + 8 sticks = 170 sticks. Then divide the total number of sticks by the number of sticks she burns per hour to find the total number of hours she can keep warm: 170 sticks / 5 sticks / hour = 34 hours.
The answer: 34.