# New Century Maths Textbook (1 Viewer)

#### Plm004

##### New Member
I need help with the working out of some answers. I have a dodgy as hell teacher who just leaves us to do the work in the text book without giving us any help, and i was wondering if anyone can help with the actual working out or know where i can find the workings for answers online?
It's the New Century Maths 12 3rd edition Mathematics General 2 texbook.

#### dan964

##### MOD
Moderator
I need help with the working out of some answers. I have a dodgy as hell teacher who just leaves us to do the work in the text book without giving us any help, and i was wondering if anyone can help with the actual working out or know where i can find the workings for answers online?
It's the New Century Maths 12 3rd edition Mathematics General 2 texbook.
Best to post questions you are struggling with, here, and people will answer; as this would be better.

#### Plm004

##### New Member
Best to post questions you are struggling with, here, and people will answer; as this would be better.
Good idea. Thank you.

#### Plm004

##### New Member I'd like help with the workings of c

#### Bliske

##### New Member
So its asking you the simple interest rate per annum so we know that the formula I=PRN should be used, which you should be familiar with. We know that they must pay \$92 per week for five years, which totals to \$23920. This amount (\$23920) minused from the principal (shown below) is the total intrest they payed: \$8630

We know the principal is (total cost of car - deposit) \$15290 which is how much they borrowed to buy this car.

We also know that they payed this back over five years.

Now we can solve for the rate per annum by substituting values into I=PRN

8630=15290 x r x 5

R x 100 = 11.2884...%

Which means the answer is 11.3% per annum (to one decimal place).

• BLIT2014, Mosski and Plm004

#### Plm004

##### New Member Could anyone help me with Q5 A and B. Thanks

#### Bliske

##### New Member Could anyone help me with Q5 A and B. Thanks
Ok, so for part A its asking for total cost of the yacht. We can work this out by using the table provided. We should first work out how much just directly we are borrowing to purchase this yacht. The table states its \$47 500, which we will then use to subtract the deposit and the trade in allowance to work out the amount borrowed.

As an aside, the question is a little bit ambiguous if the trade in subsidises the actual amount you borrow, so this answer may be wrong, but it makes the most logical sense.

This amount is the principal in the I=PRN formula. We know to use the I=PRN formula as the table states it is a flat interest rate and it is at 15.8% p.a over five years. We then put this into the formula to work out the total interest we have to pay: I= 35 600 x 15.8% x 5. This gives a interest value of \$28124, which we then add back to the principal (\$35 600) which gives us a total cost of \$63724 for the yacht directly. Their is also other charges' such as stamp duty (\$475) and registration (\$1203) we must also add, as well as adding back on the deposit (\$6500).

This gives us a final answer of \$71902 for part A.

For part b, its asking for the monthly repayments, excluding the other charges, and also excluding the deposit as it is an upfront payment and its not monthly. We already worked out from part A that the total cost of of yacht (principal + interest) is \$63724. This is the amount they pay over five years so if we divide this by the amount of months in five years (60 months) we will get the following working out: \$63724 / 60 = 1062.07

The answer for part B therefore is \$1062.07 per month.

Also, feel free to directly PM me however many more questions you have as I'm happy to help whenever.

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