Substance Word Problems

C

chantalstamp

New member
Joined
Sep 28, 2008
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6
How much molten steel that is 40% iron must be mixed with molten steel that is 10% iron to obtain 1000 lbs of steel that is 37% iron?

I need help setting up the problem, I have no idea where to go.
 
One equation in one unknown or two equations in two unknowns?
 
Example:
How much 70% alcohol must be mixed with 95% alcohol to obtain 100 ounces of 90% alcohol ?

Let x = ounces at 70% ; then 100-x = ounces at 95%

[70x + 95(100-x)] / 100 = 90 : solve to get x = 20

Handle yours same way...
 
chantalstamp said:
that makes no sense whatsoever
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Actually, the tutor's explanation and complete set-up are fairly standard for this sort of exercise.

Placement tests can, unfortunately, sometimes fail, placing the student is a too-advanced course. The best solution is to drop back to where they should have started you, so you can pick up all the missing background information. The fact that you understood none of it indicates that you may need to conference with your academic advisor as soon as possible regarding appropriate course placement.

Good luck! :D

Eliz.
 
I started young, and I have no where else to go with math. There are no other lower math courses that I haven't taken. I dropped calc for this class.
 
chantalstamp said:
I have no where else to go with math.
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I'm sorry (and very surprised) to hear that your college or university has no lower-level course offerings, and that no community college or night school in your area offers anything, but there ought to be some other option. (To be fair, I spent a few years at an appalling school, and lived out in the "boondocks" with no other options, so I can certainly sympathise with the situation. But my experience was some years ago. One would like to think we've made some progress since then!) :shock:

Have you looked into private tutoring? Most high school's guidance or math offices can make recommendations, and the math department at your school might have some names, too. By working face-to-face with you, your tutor will be able to "see" what you are needing to know, figure out where the gaps are, and then provide the necessary hours of private lessons. :idea:

My best wishes to you! :D

Eliz.
 
chantalstamp said:
... There are no other lower math courses that I haven't taken. I dropped calc for this class.
Click to expand...

It sounds like you forgot the prerequisite material for Introductory Calculus, so you backed up a class. Are you also trying to say that you've forgotten the prerequisite material for this precalculus class, as well?

Perhaps you need to retake one or more of those lower math courses that you took when you were so young.

I went to college in my 30s. I was an A- student in all junior- and high-school math courses (except high-school geometry, where I got a D+). I began college at a two-year school, and the placement test put me into MATH085, the first remedial algebra class offered.

It was a very wise placement decision for me. I went on to earn an Associate of Science degree with a 3.98 GPA. If I had tried to cut corners, I would not have been nearly as successful.

THERE ARE NO SHORTCUTS in mathematics education. Either we wait until we've "got it" in the current level before we proceed to the next level, OR we go backwards to "get" what we should have "got" before.

Or, of course, we can continue forward in blindness with the acceptance that we will not complain about our subsequent struggles and failures.

If you do not have the option of starting where you actually belong, then Elizabeth's suggestion of face-to-face tutoring is definitely the way to go because you are in need of instruction at a level beyond what can be accomplished over the Internet.

~ Mark :)
 
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