finance math (1 Viewer)

[stressedadfff]

can someone pls explain why its a



and this plssss

 

[GoldenMelon]

So for the first one let Bn denote the amount of money in the account at the end of n years. So B1 would be $320, but note that interest has not been applied yet since it was deposited at the end of the year. B2 would be 320(1.07) + 320, which is the amount after interest has been applied to the original amount but then another 320 was deposited on top of it. Similarly, B3 would then be 320(1.07)^2 + 320(1.07) + 320. So you can then use the GM formula to sum them up which will give you A.

For the second I think its just 0.8 x (1.12)^12? Should be D then if I’m not wrong lol.

 

[stressedadfff]

So for the first one let Bn denote the amount of money in the account at the end of n years. So B1 would be $320, but note that interest has not been applied yet since it was deposited at the end of the year. B2 would be 320(1.07) + 320, which is the amount after interest has been applied to the original amount but then another 320 was deposited on top of it. Similarly, B3 would then be 320(1.07)^2 + 320(1.07) + 320. So you can then use the GM formula to sum them up which will give you A.

For the second I think its just 0.8 x (1.12)^12? Should be D then if I’m not wrong lol.

ohhhh how do you realise that interest has not been applied yet i think thats what confused me

thanks!

 

[stressedadfff]

alsoo does anyone know how to do the following ive completely forgotten sequences

 

[GoldenMelon]

ohhhh how do you realise that interest has not been applied yet i think thats what confused me

thanks!

The give away that interest rate has not been applied initially is that the question said the money was deposited at the end of the year. For your money to earn interest it has to sit in the bank for a while. With these questions you must read them extremely carefully because if it said the money was deposited at the start of the year then the equation will look a tiny bit different

 

[GoldenMelon]

alsoo does anyone know how to do the following ive completely forgotten sequences
View attachment 32978

We need to find the amount of rows there are before we can find out the number of cans in the bottom row. The sequence will look like this 1 + 3 + 5 + … + a = 529

We will use Sn = n/2 (2a + (n-1)d) where d = 2 (common difference) a=1 (first term)

Therefore, 529 = n / 2 (2 + 2(n-1))

Solving this gets you n = 23 meaning that there is 23 rows of cans.

Since the 1st row has 1 can, then the 23rd row will have 1 + 2(22) = 45 cans on the bottom row.

 

[5uckerberg]

View attachment 32976


can someone pls explain why its a



and this plssss
View attachment 32977

Let me shoot 2 questions in one reply. Here, the first question is just a simple application of the sum of the geometric series. Note this, look at what the question is asking you (end of year or beginning of the year). In this case it is the end of the year so our plan of attack is like this . Since this is a very common HSC question let me generalise the pattern of thought associated with these types of questions. The formula is usually

for the start of the year and
for the end of year.

Now, this is only good for annually but if they are asking for monthly divide the r by the specified amount.
Note this is depositing.

For loans it is often referred to as A_{n}=Compound interesgt formula-Deposit for the end of year formula.

For the second question it is just a simple compound interest question.

For your third question chuck in the refernce sheet formula. starting with 1 and common difference as 2. Rest is history.

 

[stressedadfff]

thansk guys!!!!

 

[stressedadfff]

does anyone know b im so confused


and this

 

[5uckerberg]

Sandra's parents are donating at what time of the year? Start of year then you know what to do, formula provided.
for the start of the year and
for the end of year.

First Edward's money is a compound interest question which is simply and n will be found by dividing by 2 for years as this is a half-yearly compounded interest.

P for principal which is the amount of money deposited and r being rate of interest and n for number of times this investment is done.

 

[stressedadfff]

Sandra's parents are donating at what time of the year? Start of year then you know what to do, formula provided.
for the start of the year and
for the end of year.

First Edward's money is a compound interest question which is simply

P for principal which is the amount of money deposited and r being rate of interest and n for number of times this investment is done.

thank youuu
could you please explain the edward one i dont really understand how to the solution for the 'half yearly' one like how to set it out?

jksss just saw the edit, thanks heaps!!

 

[stressedadfff]

hi guys can someone pls explain this, why on earth is m with 0.02 and 1.02 if the interest rate is 6%

 

[5uckerberg]

[/QUOTE]

hi guys can someone pls explain this, why on earth is m with 0.02 and 1.02 if the interest rate is 6%

View attachment 32983

For loans, it is often referred to as A_{n}=Compound interest formula-Deposit for the end of year formula. or where is the amount that has to be repaid, and the second formula is found like this . Since we have all that info now we will start. P referrs to the principal value which is the amount you take out as a loan. and that 1+r section should be 1.005. Here, the equation is like this .

Step 2.
and next . I think this question is clearly incorrect but the scaffolding for this question is shown.

 

[CM_Tutor]

A 1.02 term for 6% interest pa would apply if the year was divided into 3 blocks of four months, which would be unusual. Yearly (1.06, 5 time units), half-yearly (1.03, 10 time units), quarterly (1.015, 20 time units), and monthly (1.005, 60 time units) are common, though.