Lesson 5.3: Solving Proportions was introduced, modeled, and practiced in class. Mr. Giomini modeled two different algorithms to solve for the missing variable and encouraged students to use the cross-product with one-step equation method because it will help them later on as the numbers begin to be less friendly.
P.O.N. 12.01.14
In a shipment of 400 parts, 14 are found to be defective. How many defective parts should be expected in a shipment of 1000 parts?
Answer to P.O.N. 11.25.14: These two pay rates are not proportional. I set up the ratio pay over hours worked and calculated the unit rate for each young man. Marc earned $5.75 per hour and Marko earned $6.00 per hour. For them to be proportional, each young man would need to earn the same hourly pay.
Answer to P.O.N. 11.25.14: These two pay rates are not proportional. I set up the ratio pay over hours worked and calculated the unit rate for each young man. Marc earned $5.75 per hour and Marko earned $6.00 per hour. For them to be proportional, each young man would need to earn the same hourly pay.
- understand the concept of a ratio.
- use ratio language to describe a ratio relationship between two quantities.
- use ratio and rate reasoning to solve real-world and mathematical problems.
For Evening Practice, the student is expected to...
- complete page 14 and 15.
There should be 3.5 parts are detective for every 1000 parts. I got my answer by comparing the two units that they are using( which is parts and how many detectives are found in the part.) It is a ratio so you can make the problem like 400parts:14dectives, 400 parts/14 detective, or 400 parts to 14 detective. Once you set it up like one of the following you have to then know that they want 1000 parts. So, what you do next is make the problem like 400 parts/14detective = 1000 parts/ m. We put "m" because we don't know what "m" stands for. Now their are 2 ways to solve this, you can do cross multiplication or you can figure out what you multiplied 400 by to get 1000. Well since noting by 400 can get you to 1000 you should do cross product. When you do cross product you multiply across. In this case you have to multiply 14 and 1000 and 400 and "m". Well we know that 14 times "m" is 14,000. Next to figure out what "m" equals you have to do the opposite of what the problem says. Last you have to divide 14,000 by 400 and you would get 3.5 detectives for every 1000 parts.
ReplyDeleteKnicksterblossom
Knicksterblossom,
DeleteI like the cross multiplication algorithm that you used. Your work came down to exactly what I had, 14000 divided by 400. Look back at the original question, if there are 14 defective parts out of 400, does only having 3.5 defective parts when you have a 1000 parts seem appropriate. My thinking is that you have a decimal mistake somewhere in your division.
330 parts were defective. I got this because you cross multiply 14 * 1000 and get 14000. then you cross multiply 400 * d and get 400d, but we want to find out how much 1d is so you do 400\400 cancels out. Then you do 14000\400 is 330. That is how I got 330 defective parts.
ReplyDeleteSean,
DeleteI like all of your cross multiplication that you explained. You cam down to what I did with what is 14000 divided by 400. However, I did not get an answer of 330. Estimate how many times 4 goes into 140 and then see if your answer of 330 still makes sense.