Math Help

[Trekker4747]

Ok, I'm helping my SiL with her college math class -which is a basic math course ("Fundamentals of Math 111'") anyway we've encountered a problem that is confusing her, me and my mother because the "logic" of the problem and how it's solved aren't equaling.

First of all, her teacher wants her to do the solving using diagrams and the homework she has (as well as the text book) are very grade-school. But I guess that's just the nature of this class.

Anyway, here's the problem that has us all scratching our heads.

A bottle contains 3/8 of a liter of milk. Jerry drinks 2/3 of it. How much milk is left in the bottle?

My mind instantly tells me "1/8 of a liter."

Right?

If you made a diagram with eight segments in it (depicting the eighths of the milk bottle) and shaded in three of them (depicting the original 3/8 of a liter in the bottle) you'd have a representation of this problem, right?

So if you drink 2/3 of 3/8 whouldn't that be 1/8 of the bottle is left (removing two of those three segments leaving us with one of those segments left, or 1/8.)

But if you do the math of it, multiplying 2/3 and 3/8 you get 6/24, or 1/4.

Which, well, doesn't make sense. Does it?

 

[DonIago]

2/3 of 3/8 is 1/4...but you need to subtract that from the 3/8. 1/4 is how much Jerry drank, not how much is left.

 

[Lookingglassman]

I say drink the rest of the milk and call it empty.

 

[Trekker4747]

2/3 of 3/8 is 1/4...but you need to subtract that from the 3/8. 1/4 is how much Jerry drank, not how much is left.

Ah! That's what I was missing.

Thanks, now it makes a whole lot more sense. God, me, my mom, and sister in law were struggling and stuggling over this. The "logic" of it wasn't making sense my working it out compared to the practicality of it (the diagram.)



Somehow in the mess I missed a step.

God, I feel stupid now, and so far I've done pretty good on helping her with this math.

 

[Lookingglassman]

Dont feel stupid. I failed my one and only math class in college. I had a Chinese dude as the teacher and I couldnt understand a word he was saying so I basically gave up.

 

[JonathonWally]

I've dropped classes if a professor had an accent that was too tough for me to understand.

I also dropped an English class one time because the prof was VERY cross-eyed and I just couldn't take it. Nice lady, but those fuckin eyes fucked with me.

 

[Lookingglassman]

JonathanWally,

For a history class I needed to graduate I had another Chinese teacher. He was an old coot who never smiled. He was teaching 20th Century History. When we got to World War II he spent 10 minutes on the European Theater of war, but TWO WEEKS on the Pacific Theater. I couldnt believe it. His WW II European history class was basically, "Hitler was bad. He invaded different countries. The allies invaded France. Germany surrendered on May 7, 1945. Any questions?"

 

[Meat Tenderizer]

Ok, I'm helping my SiL with her college math class -which is a basic math course ("Fundamentals of Math 111'") anyway we've encountered a problem that is confusing her, me and my mother because the "logic" of the problem and how it's solved aren't equaling.

First of all, her teacher wants her to do the solving using diagrams and the homework she has (as well as the text book) are very grade-school. But I guess that's just the nature of this class.

Anyway, here's the problem that has us all scratching our heads.

A bottle contains 3/8 of a liter of milk. Jerry drinks 2/3 of it. How much milk is left in the bottle?

My mind instantly tells me "1/8 of a liter."

Right?

If you made a diagram with eight segments in it (depicting the eighths of the milk bottle) and shaded in three of them (depicting the original 3/8 of a liter in the bottle) you'd have a representation of this problem, right?

So if you drink 2/3 of 3/8 whouldn't that be 1/8 of the bottle is left (removing two of those three segments leaving us with one of those segments left, or 1/8.)

But if you do the math of it, multiplying 2/3 and 3/8 you get 6/24, or 1/4.

Which, well, doesn't make sense. Does it?

The trick is to multiply 3/8 by 1/3 (1/3 representing the amount of milk he did not drink).

 

[DonIago]

^Wow, so that's what it feels like when your thunder gets stolen.

I always did reasonably well in math up until Calculus (shudder). Though I was better in English.

Stupid story- Took the SAT's, got a 610 English, 590 Math. Guidance counselor, in front of my parents, was all "That's really good...but it would be great if he could get over 600 in both..."
No shit, the next time I took the SAT's I got a 620 English and a 580 Math. Time and energy well-spent...couldn't have planned that any better if I'd tried.

In terms of awkward classes, I had a history class in a stuffy part of my college campus where the teacher was...pretty old...and it turned out there were about 5 of us. I seriously thought the class would end up canceled. Never happened. If I hadn't needed the credit...

 

[Trekker4747]

Well, I knew the answer instantly just by thinking of it, what got me mixed up was showing "the work" of it and the work I was coming up with wasn't matching the diagram the teacher wants.

It's funny, though, that the teacher wanting college students to do math by making pictures ended up coming up with a clearer solution than doing the math of it, however, if the teacher had explained to DO THE MATH of it this wouldn't of been an issue.

And I feel so stupid for not getting this, for my defense I'm going to say that in the commotion of dealing with my mother and SiL and working this problem out I wasn't in my full mind.

Yeah, that's it.

 

[Nerys Ghemor]

JonathanWally,

For a history class I needed to graduate I had another Chinese teacher. He was an old coot who never smiled. He was teaching 20th Century History. When we got to World War II he spent 10 minutes on the European Theater of war, but TWO WEEKS on the Pacific Theater. I couldnt believe it. His WW II European history class was basically, "Hitler was bad. He invaded different countries. The allies invaded France. Germany surrendered on May 7, 1945. Any questions?"

My guess is that when he was in school back in China, he studied the Pacific Theater in a LOT of detail. (Remember the invasion of Manchuria? NASTY business, that...) But not so much the European Theater. Though that is very surprising that learning those facts would not be a prerequisite for teaching in the US...

I've dropped classes if a professor had an accent that was too tough for me to understand.

I never once, not even a single time had that problem, even in classes where a lot of the other students were complaining about the professor's accent. Give me a day or two and I can pick up pretty much any accent--even more quickly if I know even a little bit about the person's native language. I think that's just one of my peculiarities, that I don't have trouble with accents for very long.

I think the other thing was that in those classes, I was willing to TALK with the instructor...to ask questions in and after class. That's the thing that I think a lot of people miss--time and greater exposure do help, and if you're willing to actually put forth the effort, that will help at least some.

 

[JonathonWally]

I've dropped classes if a professor had an accent that was too tough for me to understand.

I never once, not even a single time had that problem, even in classes where a lot of the other students were complaining about the professor's accent. Give me a day or two and I can pick up pretty much any accent--even more quickly if I know even a little bit about the person's native language. I think that's just one of my peculiarities, that I don't have trouble with accents for very long.

I think the other thing was that in those classes, I was willing to TALK with the instructor...to ask questions in and after class. That's the thing that I think a lot of people miss--time and greater exposure do help, and if you're willing to actually put forth the effort, that will help at least some.

My university had a lot of international professors, since at the time it was one of the few that offered a serious diplomacy major/program so lots of international students and teachers. While I didn't have a problem at all 99% of the time, there was 2 profs that were very very hard to understand, it wasn't just thier accent but that their english wasn't in great shape. Very smart people, just very very hard to grasp, one in particular didn't use a white board or the overhead computer projector and did only lectures, so I just couldn't do it. It was also a hard class, so instead of hurting my GPA, I dropped the course, took another, then took that class later on with a different prof.

 

[nx1701g]

I hated my algrebra classes in college. Thank God that's over.

 

[archeryguy1701]

You had the right idea. The strategy is to get the top number so that it can be divided by three. In this particular case, the top number was where you needed it to be (3), so you just take 2/8 of your 3/8 away. On the other hand, if the problem was "Jerry has 5/8 of a liter and he drinks 2/3. How much is left?", then you just multiply 5/8 by 3/3, so you end up with 15/24. From there, you take away 2/3 from the top, which would leave you with 5/24. Then in some cases (not this particular example), you just reduce and you have your answer.