<p>Ok so there's this math question that i did on my practice test yesterday and i got a different answer than what the Barron's book has. </p>
<p>Q: When 25 students took a quiz, the grades they earned ranged from 2 to 10. If exactly 22 students passed, by earning a 7 or higher, what is the highest possible average (arithmetic mean) the class could have earned on the quiz? (this was a grid in question)</p>
<p>And another one. I had this question with a diagram with angles involved and the question was regarding that, but there was a note that said picture is not to scale. I thought that if the picture wasnt to scale you couldnt trust it, so you should draw your own picture. But this book, uses that same picture with nothing different. So what should i do in those cases? Trust the picture (like the book does here) or make my own (which i usually do)?</p>
<p>Thanks!</p>
<p>You have to maximize. 22 students got 10, and the other 3 got 6.
It’s all simple algebra from there: [22(10) + 3(6)]/25 = 9.52.</p>
<p>Hmmm, the fact that the picture isn’t to scale means you shouldn’t go measuring the angles or trying to eye their proportions. That’s all. Use your discretion. After all, a picture you draw wouldn’t be to scale either.</p>
<p>For the highest possible average, each kid needs to get the highest possible score. If 22 kids passed, the best case scenario is all of them got 10. 3 kids failed so the best case scenario for them is all of them got 6. 22(10)+3(6)=238. 238/25=9.52 so the highest possible average is 9.52.</p>
<p>Just because a picture says not to scale doesn’t mean you should ignore it. In regular pictures you can get away with eyeballing certain angles. For example if problem asks you to find angle x, which is slightly obtuse, and you get 100 degrees for an answer, you can assume you’re probably right. In not to scale pictures you can’t do this and you have to use pure math and knowledge of angles.</p>
<p>ya i got 9.52 as well. But my barron’s book said that you do this: (22<em>10)+(1</em>2)+(2*6) = 234/25 = 9.34 instead of 9.52. they said that 1 one of the scores has to be 1 for some reason. As for the picture, there was nothing given except a picture with the note, and a question asking which of these is true, so i didnt know how to recreate the picture.</p>
<p>Ohhhh, I see. One of the scores has to be TWO because the range of the scores if from TWO to TEN.</p>
<p>It makes sense now. 22(10) + 2(6) + 2 = 234/5 = 9.34. I don’t think the question was well presented, though.</p>
<p>But why would you use a 2 when you’re talking about the highest average? If you do 22<em>10 + 3</em>6 you get 258, which divided by 25 is 9.52 and is thus greater than 9.34. how does that work out?!</p>
<p>The range is 2-10, thus you must have the high and low value in the final groupings</p>
<p>what?..im completely lost. can you tell me where you got that high and low value thing?</p>
<p>teteatete and icancel are trying to say that the range is 2-10. therefore, one of the scores MUST BE 2 and another MUST BE 10 in order for range to go between those values. if you solved it the previous way (22<em>10+6</em>3), then the range would be 6-10. tricky problem that tricked everyone posting.</p>
<p>oh ok. well when do you follow that rule? because thats the first time ive seen that rule in my life. no joke.</p>
<p>To be honest this is a stupid question because it can be interpreted two different ways and can give two different answers. This question would never appear on an actual CB test, at least without clarification.</p>
<p>Yeah, first question is rather ambiguous. I would believe that if the scores ranged from 2 to 10 then there would be at least one score of 2 and at least one score of 10 (otherwise it might as well say, “ranged from 6 to 10”). It seems like the answer would be (22(10) + 2(6) + 1(2))/25 = 9.36.</p>
<p>If the diagram says it’s not to scale, realize that it is “not necessarily” to scale (there’s a difference). However, I would just assume it’s not to scale and draw a new one.</p>
<p>CB better not put these types of questions on tests. Even if you do, you can file a complaint.</p>