Number Patterns Q's

[xD_aQt]

Any help would be much appreciated

Mary invests $500 in a term deposit which pays 4.5% interest compounded annually.
If she keeps the term deposit for 10 years, how much interest will she have earned?

[stonecold]

Use tn=ar^n as you are working with t0, the initial term, before anything has happened.

Convert 4.5% to decimal = 0.045
As it is an increase, the ratio will be 1 + 0.045 = 1.045

t10=500 x 1.045^10 = 776.48

Interest earned = final amount - initial amount
                      = 776.48 - 500.00

$276.48

For knowing which formula to use, check:
http://vcenotes.com/forum/index.php/topic,19085.msg192328.html#msg192328

[xD_aQt]

^ Thankyou

A certain kind of bacteria reproduces itself at a rate such that the number of bacteria doubles every 38 hours. Initially there were 100,000 bacteria in a laboratory jar. How many bacteria will there be in 9.5 days?

[stonecold]

Okay. Firstly convert 9.5 days to hours.

9.5 x 24 = 228 hours

Treat each 38 hours as 1 period.

To work out the number of periods in 228 hours, divide it by 38.

228/38=6.

Now we have all the info which we need to work it out.  Ratio is 2, as we are doubling.

t6 = 100,000 x 2^6 = 6,400,000 bacteria in 9.5 days.

[xD_aQt]

^ Apparently the answer is 3,200,000 ?

[stonecold]

I think there is an error in the book, as I did a bit of a table thing, and i still get that answer.

0=100,000
38=200,000
76=400,000
114=800,000
152=1,600,000
190=3,200,000
228=6,400,000

[xD_aQt]

Oh okay How would you set up a table on the Ti-Nspire ?

[stonecold]

GO to lists and spreadsheets.

In column A, next to the little A type 'n'

Then underneath it, in each cell, put in your term numbers (Start underneath the grey box).  So 0,1,2,3,4,5,6,7....  You don't have to do too many.

In column B, leave the top bit blank.
In the grey box underneath it, type '100000x2^n'.  Then it will ask if n is a column reference or variable reference.  Select variable reference.  

And voila!  You should have everything in a nice little table.  

[kenhung123]

Wow is number patterns al calculator work?

[Albeno69]

Wow is number patterns al calculator work?

yea i did all min last yr on calc  but not sure if i can afford to do it in exam cos stupid school isnt doing it, an cbf learning it.

[xD_aQt]

Does anyone have any Practice Tests for Module 1: Number Patterns ? Any would be much appreciated!

[xD_aQt]

There are 30,000 zebras in Horadina. The number of zebras decreases by 4% each year due to poaching. Also 5,000 zebras are born each year, but 1,500 die in infancy.

• Write down a difference equation to describe the zebra population in Horadina.
• How many zebras are there in Horadina at the end of the third year?

[stonecold]

tn+1 = 0.96tn + 3500 where t0=30000

t1 = 0.96 x 30000 + 3500 = 32300
t2 = 0.96 x 32300 + 3500 = 34508
t3 = 0.96 x 34508 + 3500 = 36627.68

36628 zebras

Edit: It is actually probably 36627, as you can't round up for animals...