tailieunhanh - Geomegy review 4

Tham khảo tài liệu 'geomegy review 4', ngoại ngữ, anh ngữ phổ thông phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | --------------------------------------- PROBLEM SOLVING ------------------------------------------------ Practice Question The number a is directly proportional to b. If a 15 when b 24 what is the value of b when a 5 a. 5 b. ạ c. 8 d. 14 e. 72 Answer c. The numbers a and b are directly proportional in other words they vary directly so a increases when b increases and vice versa. Therefore we can set up a proportion to solve 24 5 Find cross products. 15b 24 5 15b 120 15b 120 15 15 b 8 Therefore we know that b 8 when a 5. Rate Problems Rate is defined as a comparison of two quantities with different units of measure. R t _ X units Rate y units Examples dollars cost miles miles hour pound hour gallon There are three types of rate problems you must learn how to solve cost per unit problems movement problems and work-output problems. Cost Per Unit Some rate problems require you to calculate the cost of a specific quantity of items. Example If 40 sandwiches cost 298 what is the cost of eight sandwiches First determine the cost of one sandwich by setting up a proportion 238 _X _ 40 sandwiches 1 sandwich 159 -------------------------------------- PROBLEM SOLVING ---------------------------------------------- 238 X 1 40 Find cross products. 238 40 238 _ 40 Now we know one sandwich costs . To find the cost of eight sandwiches multiply X 8 Eight sandwiches cost . Practice Question A clothing store sold 45 bandanas a day for three days in a row. If the store earned a total of from the bandanas for the three days and each bandana cost the same amount how much did each bandana cost a. b. c. d. e. Answer a. First determine how many total bandanas were sold 45 bandanas per day X 3 days 135 bandanas So you know that 135 bandanas cost . Now set up a proportion to determine the cost of one bandana _ 2 U J 135bandanas 1 bandana X 1 135 Find cross products. 135 135 Therefore one .