Why did you guys remove {x}

Sorry, it was a typo. I've put it back in post #9.

]]>Q!. Correct.

Q2. Divide each side by 2, square and subtract 4.

Q3. If you square both sides you'll see this has a solution. (I'm assuming a square root could be + or - )

Q4. Simplify the bracket. Do you see that square root amongst the answers?

Q5. You could square both sides, re-arrange and re-factorise. But what I did was try the possible solutions to see if any fit. I got an answer straight away.

Bob

]]>Can you describe the problem a little better?

]]>Let me know if you get anything out of it.

]]>Hi auyeungyat;

To get an answer of 2 you would need to put a bracket around that 9 + 3.

]]>I'll try to cover all those questions in a mo. I'm a retired Uk maths teacher so I'm used to GCSE and A level syllabuses. These give much more detail than this:

http://www.cii.co.uk/media/5454608/j10_ … -15_v4.pdf

which I assume is what you are working towards. For instance, you'd get the required formulas and a (free) specimen exam paper plus lots of past papers also free. I'm also assuming you have one or more texts that give you some ideas about what to learn.

If you have an amount P and you want to add 5% interest then you'd do this:

But you'll get the same answer like this:

The number 1.05 is very useful when doing compound interest because you can keep applying the same multiplier again and again to the principle amount.

Also if you have to get the equivalent monthly rate you need to start with the yearly multiplier (1.05) and find the twelfth root:

That's the right multiplier to use throughout the question so that's what 'r' stands for everywhere. If I had different rates at different places in a formula I would use different symbols as needed.

I discovered that it is common elsewhere (ie. not the UK) to get a monthly rate by dividing the yearly rate by 12. Watch out for formulas you get off the internet in case they do this.

I hope that answers questions 1 and 2.

Q3. In algebra x is often used so it can get confusing if x is also used as a times sign. So you'll often find a dot used instead. So W.a just means W times a

Q4 I'll re-arrange my formula so W is the 'subject'. You want to know W so that after n= 96 (months) there is no money left.

The geometric progression (GP) is

This has first term a = 1, common ratio r = 1.004074123, and n = 8 times 12 = 96. I can leave the 'a' out as it is one:

with the above values:

So with a different annual rate (I), start by calculating the monthly rate:

and then for a starting amount P

Hopefully that deals with Q5.

I'm still a bit worried about this business of getting the monthly rate. Your question is in $ and the given answer is $316. That's what I got by doing 1.05 divided by 12 and also what bobbym got. They use this method (1.05/12) in the USA where bobbym hails from. Cii is a UK institute so why are they using a question with $ and a US method of calculating the monthly rate? It might be wise to query this with cii.

Hope that helps,

Bob

]]>Any ideas on this one?

]]>It may be worthwhile to learn the general formula I gave as it could help deal with a tricky exam question.

]]>I tried S=the thing posted and S/3, not exactly sure how to do it, I have 3^k/(3^k+1)

You can not pull the 3 out of the log like that.

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