Guest guest Posted April 10, 2008 Report Share Posted April 10, 2008 Hi Everyone, I'm working on some ratio and proportion practice questions and I'm stuck. Here is the question along with the calculation that I made. How many avoirdupois ounces are in 1 kg? 1 oz ? ---------- = ------- .0284 kg 1 kg ? x .0284 kg = 1 oz x 1 kg ? = 1 oz x 1 kg ------------- .0284 kg ? = 1 ----------- .0284 oz This was my final answer, but the answer key says the correct answer is 35.21 Can someone provide me with some guidance? Mike Quote Link to comment Share on other sites More sharing options...
Guest guest Posted April 10, 2008 Report Share Posted April 10, 2008 Dear Mike, Everything appears correct, except your final step is not complete. continue in the calculator to divide 1oz by by 0.0284 kg /oz = answer is 35.211267..... Which when rounded to the nearest 1/100 will be: 35.21 oz (ounces) Hope this helps, Jeanetta Mastron CPhT BS Pharm Tech Educator Founder/Owner > > Hi Everyone, > > I'm working on some ratio and proportion practice questions and I'm > stuck. Here is the question along with the calculation that I made. > > How many avoirdupois ounces are in 1 kg? > > 1 oz ? > ---------- = ------- > .0284 kg 1 kg > > ? x .0284 kg = 1 oz x 1 kg > > ? = 1 oz x 1 kg > ------------- > .0284 kg > > ? = 1 > ----------- > .0284 oz > > This was my final answer, but the answer key says the correct answer > is 35.21 > > Can someone provide me with some guidance? > > Mike > Quote Link to comment Share on other sites More sharing options...
Guest guest Posted April 10, 2008 Report Share Posted April 10, 2008 Hi Mike, I can tell your book uses exact measurements which is nice but means you have to understand that both dry and wet (liquid) measurements are different. In this case dry measure is 1 oz = 28.35 grams and wet measure is 1 oz = 29.57 ml. To solve how many dry ounces is in 1 Kilogram? Setup 1 oz / 28.35 grams = x oz / 1 Kg Since your proportion contains 2 equal ratios, the units have to be the same on top and on bottom. In this case the units on top match on both sides, but units on bottom do not match on both sides, so you need to make them match by either changing Kg to grams or grams to Kilograms. Let's change Kg to grams which is 1000 grams. New Setup: 1 oz / 28.35 grams = x oz / 1000 grams x = 35.27 oz For the national exam, using 1 oz dry and 1 oz wet can be equal to 30 grams or 30 ml (approximate)...makes life much easier. Of course I may get criticized or ostracized by saying this as some believe that you must be EXACT as possible. If this is the case then we can argue that 4 oz does not really equal 120 ml that we learned in school. Joe Medina, CPhT Quote Link to comment Share on other sites More sharing options...
Guest guest Posted April 10, 2008 Report Share Posted April 10, 2008 Boy what a coincidence being on line at the same time or nearly! I would AGREE 100% with Joe (no ostracizing here) that using 30 gm or 30 ml is what is used on the PTCB AND I will add in some compounding settings as well. And definitely in retail with oral liquids. While the actual numbers are slightly less than 30 gm or 30 ml this is WHY 1 pint is 16 ounces is equal to either 500 ml 480 ml or 473 ml depending upon which you use for conversion of the ounces to ml and where you round. The same can be applied to GRAIN where the more exact numbe is 64.8 mg.... so it is rounded to 65 mg/grain and some companies use 60 mg/1 grain. There is a place and time that those in the KNOW have decided for all of us that it is SAFE and ACCEPTABLE to use rounded conversion factors. If you need to be exact you can always use the exact number. But for most work in the pharmacy 30 grams fro dry ounce and 30 ml for liquid/fluid ounce is sufficient. I STOPPED teaching this 'exactness' a long time ago! I used to teach it and I found it was used less and less in the real world. By the way is there any one out there who IS using the 'exact' conversions factors of : 1 dry oz = 28.35 grams and 1 fluid oz = 29.57 ml ??? IF so can you provide us with the example of how and when you use it on the job? Now i WANT TO MAKE IT CLEAR THAT I do explain to my students the exact numbers and why we use the 30 grams and 30 mgs instead of the 'exact' numbers. By the way even the exact numbers have been rounded! So my students do have knowledge when they go out into the real world if they should happen across a job that requires them to use these 'exact' amounts where they came from, and they can use them in the SAME mathematical ratio/proportion set up method to get the correct amount. Thanks for your explanation, Joe Respectfully to all, Jeanetta Mastron CPhT BS Pharm Tech Educator Founder/Owner > > Hi Mike, > > I can tell your book uses exact measurements which is nice but means > you have to understand that both dry and wet (liquid) measurements are > different. In this case dry measure is 1 oz = 28.35 grams and wet > measure is 1 oz = 29.57 ml. > > > Joe Medina, CPhT > truncated by Jeantta Mastron Quote Link to comment Share on other sites More sharing options...
Guest guest Posted April 10, 2008 Report Share Posted April 10, 2008 By the way I don't teach scruples, pennyweight or troy ounces any more either! Any one out there still teaching this stuff? If so may I ask how and when it is used on the job? Perhaps it is used in an area that I am not familiar with, such as nuclear pharmacy? Any way I hve NOT had any complaints from any of my live classroom students who all must take the PTCB or the members of this site who take the PTCB exam. NO ONE has ever asked me why I don't teach scruples or pwt or troy oz. So I can safely say they are not on the exam. Jeanetta Mastron CPhT BS F/O > > > > Hi Mike, > > > > I can tell your book uses exact measurements which is nice but means > > you have to understand that both dry and wet (liquid) measurements are > > different. In this case dry measure is 1 oz = 28.35 grams and wet > > measure is 1 oz = 29.57 ml. > > > > > > Joe Medina, CPhT > > > truncated by Jeantta Mastron > Quote Link to comment Share on other sites More sharing options...
Guest guest Posted April 10, 2008 Report Share Posted April 10, 2008 you are missing the final step that fraction means divide (as all fractions do 1/4=0.025 for example) so plug into your calculator 1 hit the divide symbol and plug in 0.0284. you should get an answer that is a number with a decimal rather than a fraction. one of the teachers on here can teach it much better than i can. --- photography_sage <photography_sage@...> wrote: Hi Everyone, I'm working on some ratio and proportion practice questions and I'm stuck. Here is the question along with the calculation that I made. How many avoirdupois ounces are in 1 kg? 1 oz ? ---------- = ------- .0284 kg 1 kg > > ? x .0284 kg = 1 oz x 1 kg > > ? = 1 oz x 1 kg > ------------- > .0284 kg > > ? = 1 > ----------- > .0284 oz > > This was my final answer, but the answer key says > the correct answer > is 35.21 > > Can someone provide me with some guidance? > > Mike > > " If the world were perfect, it wouldn't be. " - Yogi Berra ONLY AFTER YOU'VE LOST EVERYTHING ARE YOU FREE TO DO ANYTHING like myspace? try yuwie! http://r.yuwie.com/katbird_27 if you have the time to click on an e-mail link like this one: http://www.sendmoreinfo.com/ID/2425657 you really can earn some extra cash! even easier just get paid to surf! http://www.agloco.com/r/BBBP9226 __________________________________________________ Quote Link to comment Share on other sites More sharing options...
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