1.1 Integers and Rational Numbers

www.ck12.org Chapter 13. Problem SolvingThe key is “twice as old.” This clue means two times, or double Ben’s age. Begin by doubling possible ages. Let’slook for a pattern.4 × 2 = 8. Jeff is already older than 8.5 × 2 = 10. This doesn’t make sense because Jeff is already 10.6 × 2 = 12. In two years, Jeff will be 12 and Ben will be 6. Jeff will be twice as old.Jeff will be 12 years old.Example 2: Matthew is planning to harvest his corn crop this fall. The field has 660 rows of corn with 300 ears perrow. Matthew estimates his crew will have the crop harvested in 20 hours. How many ears of corn will his crewharvest per hour?Solution: Begin by highlighting the key information.Matthew is planning to harvest his corn crop this fall. The field has 660 rows of corn with 300 ears per row.Matthew estimates his crew will have the crop harvested in 20 hours. How many ears of corn will his crewharvest per hour?You could draw a picture (it may take a while), write an equation, look for a pattern, or make a table. Let’s try to usereasoning.We need to figure out how many ears of corn are in the field. 660(300) = 198,000. This is how many ears are in thefield. It will take 20 hours to harvest the entire field, so we need to divide 198,000 by 20 to get the number of earspicked per hour.The crew can harvest 9,900 ears per hour.198,00020= 9,900Practice SetSample explanations for some of the practice exercises below are available by viewing the following video. Notethat there is not always a match between the number of the practice exercise in the video and the number of the273