There's no need to feel stupid. Like most things, fluency with basic maths tasks comes mostly from practice.
There's also "good exam practice" which assumes questions don't vary much. Try to get hold of previous papers and work through those. That's less learning to answer general questions and more learning to pass a particular exam, but it's a valid tactic. Obviously you probably already know this.
If you're stuck then collar someone for a hand (hell, even ask here).
I am trying to do as many samples as possible, but whenever I get a new book with previous papers, they seem to have strange tasks which I hevn't met before.
Like this for example: How much water has to be added to 10 gallons of 10% brine solution (what the hell is that, i have no idea) to decrease the concentration to 7%?
What the hell it is, is a bloody awful question, unless it supplies a definition. A brine solution is salt disolved in water. Unfortuantely, there are at least three ways (not including molarity, which is what chemists usually use) to measure this
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Thanks so much, correct answer and thanks for explaining! You're right, some of the questions are a bit weird, like this for example: if @ is a binary operation defined as a difference between an integer n and a product of n and 5 then what is the largest positive integer n such that the outcome of the binary operation is less than 10? Answers: 1,2,3,4,5.
I thought it would be 5 as I thought the operation goes as follows n-5n. But the answer says the operation goes 5n-n, therefore the correct answer is n=2. May be I don't understand the exact meaning of the word binary?
Actually, the person who set the question doesn't understand the word. A "binary operation" is one that takes two numbers and produces an answer. Examples are: multiplication, division, addition, subtraction
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I have to revise maths terminology as well. It is clear now what they asked for. We have two different (but similar) words in Russian for "difference", that's why I got confused I think.
Thanks a lot! It's very helpful to get such nice explanations. You're very clever :-)
There's also "good exam practice" which assumes questions don't vary much. Try to get hold of previous papers and work through those. That's less learning to answer general questions and more learning to pass a particular exam, but it's a valid tactic. Obviously you probably already know this.
If you're stuck then collar someone for a hand (hell, even ask here).
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Like this for example: How much water has to be added to 10 gallons of 10% brine solution (what the hell is that, i have no idea) to decrease the concentration to 7%?
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My attempt:
If you have 10 gallons of 10% solution, you've effectively got 1 gallon of salt.
1 [amount of salt] = (10/100) * 10 [amount of solution]
For a 7% solution from this:
1 [salt] = (7/100) * n
n = 14.286
So you need to add 4.286 gallons of water to the original solution.
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But I totally agree, what a confusing question style
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if @ is a binary operation defined as a difference between an integer n and a product of n and 5 then what is the largest positive integer n such that the outcome of the binary operation is less than 10?
Answers: 1,2,3,4,5.
I thought it would be 5 as I thought the operation goes as follows
n-5n. But the answer says the operation goes 5n-n, therefore the correct answer is n=2. May be I don't understand the exact meaning of the word binary?
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We have two different (but similar) words in Russian for "difference", that's why I got confused I think.
Thanks a lot! It's very helpful to get such nice explanations.
You're very clever :-)
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