Developing Expert Voices

By: Michelle Winter &Jessie Boyd

1. Sandra works at a clothing store. She is responsible for keeping track of items sold. She has a list of pants sold within the last two weeks. Find the mean, median and mode to help her keep track of her sales.

S M T W T F S

Week 1 34 20 26 26 27 30 35

Week 2 30 22 25 26 28 31 33QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.

2. On her lunch break, Sandra decides to go shopping. She wants to visit two shoe stores in her one hour break. From her starting point, Sandra goes 12 km/h at a 30 degree direction for ten minutes. She stays there for twenty minutes. She then walks at a speed of 18 km/h at a direction of 42 degrees east of south for another ten minutes. After ten minutes in that store she decides to return back to work. In what direction and distance does she have to travel to return to her starting point? Show all work.

3. The next day Sandra visits her favourite clothing store and walks to the sales rack. On the rack are ten shirts, blue, green, orange, yellow, purple, black, pink, white, grey, and red. Sandra loves them all, so she decides to close her eyes and choose three, since it’s al she can afford. What is the probability:

a) Both the black and the green are chosen?

b) Either the pink or purple is chosen?

c) Neither the grey or orange is chosen?

4. Sandra leaves on her straightner when she goes to work, and all her clothes burn. So she decides to use her credit card to replace her wardrobe. She ends up putting $1200 on the card. It gathers on her card for three months.

a) For the first month, no interest is added. For the two months(60 days) interest gathers at 18% compounded daily. At the end of the three months how much does she owe on her card?

b) Sandra then decides to take out a loan to pay off her credit card. They offer her 6% compounded monthly. If she wants to pay it off in 2 years, what will her monthly payments be?

Question #1:

Mean or x = 28.07Median = 27.5Mode = 26

There are two different ways to solve this question. On you calculator or by hand.

On your calculator :

STEP 1

Press STAT button on your calculator and enter all values into L1

STEP 2

Press the STAT button again but then move cursor to CALC.

Choose first option and then press enter.

STEP 3

To find the mean look at the value by the X.Then by scrolling down you will find the

MEDIAN.And the MODE is always the number that

reoccurs most in the set number of data.

By hand:

Step 1

TO FIND THE MEAN:Take all valued and divide by amount of

values given.

Example: 12+16+4 -------------

3

Step 2

To find the MEDIAN you must order the values from smallest to largest, it is the middle value.

1,2,3,4,5If it is an odd number set of data. It is the two middle

umbers divided by two.1,2,3,4

2+3 / 2 = 2.5

Step 3

The MODE is the value that occurs most often in a set of data.

Example: 1,3,6,3,7,9,2,4,3,15,22,45,3.

Question #2:

First calculate the distance that Sandra walked in kilometers.

If she walked for 10 minutes, that is 1/ 6 of an hour.

12 km/h = 12/6

= 2 km

18 km/h = 18/6

= 3 km

Then you can draw your diagram.

2 km

3 km30 degrees

30 degrees

70 degrees

42 degrees

112 degrees

Resultant vector

Since you know two sides and an angle you can go into your calculator, under

PRGM to TRISOLV to solve the triangle.

2 km

3 km30 degrees

30 degrees

70 degrees

42 degrees

112 degrees

Resultant vector

Angle A

Angle C

Angle B

Side C

Side B

Side A

With all angles and sides lettered, it will be easy to followthe TRISOLV application on you calculator.

Press the PRGM button on your calculator and go into the TRISOLV application

Enter in all the sides and angles you know, according to your diagram and then press

solve.

Draw a diagram on you paper to show the values you knew and the ones you obtained, like this:

TRISOLV

Sides Angles

a = 4.183 A = 112 degrees

b = 3 B = 41.683 degrees

c = 2 C = 26.317 degrees

(Black represents known data and red represents acquired data)

Thanks to the TRISOLV application you now know the distances of the resultant vector.

Resultant vector 4.183 km=

Now that you know the distance she must travel, the last thing to find is the direction. Which is

found on a bearing:

Resultant vector 4.183 km.=

30degrees

41.683degrees

30 + 41.683 = 71.683 degrees

(The bearing)

Therefore, the answer is:

To return back to work she would have to travel 4.183 km at a bearing of 71.683 degrees.

Question #3

a) 2C2 8C1 c) 8C3

--------------------- = 0.0667 -------------- = 0.4667

10C3 =1/15 10C3 = 7/15

b) 2C1 8C2

------------------- = 0.4667

10C3 = 7/15

To find the answer for a:

2C2

Since we are looking for two specific shirts, we are choosing two out of two.

To find the answer for a:

8C1

And since she wants to buy 3 shirts, the last one has to be counted as well. So out of the eight left, since she has already chosen two, one

more has to be picked.

To find the answer for a:

10C3

And it is divided by 10 choose 3, since we need to divide the two possibilities by the end result

of choosing the three out of ten.

To find the answer for a:

To enter the values on your calculator, you press MATH and move the cursor over to PRB and

find the nCr option

To find the answer for a:

Enter in the first number and then the nCr option after each number, placing the last number

afterward.

2 nCr 2

To find the answer for a:

Then when you have all the values put in your calculator, press enter and your answer is

given.

Since it is is decimal form, change it to a fraction.

0.0667 = 1/15

To find the answer for b:

2C1

Since we want one or another, out of the two colours we want to choose only one.

To find the answer for b:

8C2

And out of the two colours given we chose one, so that leaves two shirts to still be picked,

therefore out of the eight colours left to pick we want to choose two.

To find the answer for b:

10C3

And it is divided by 10 choose 3, since we need to divide the two possibilities by the end result

of choosing the three out of ten.

To find the answer for b:

To enter the values on your calculator, you press MATH and move the cursor over to PRB and

find the nCr option

To find the answer for b:

Enter in the first number and then the nCr option after each number, placing the last number

afterward.

10 nCr 3

To find the answer for a:

Then when you have all the values put in your calculator, press enter and your answer is

given.

Since it is is decimal form, change it to a fraction.

0.4667 = 7/15

To find the answer for c:

8C3

Since we don’t want two out of the ten shirts, we take the two shirts out of the questions and

choose three out of the eight.

To find the answer for c:

10C3

And it is divided by 10 choose 3, since we need to divide the two possibilities by the end result

of choosing the three out of ten.

To find the answer for c:

To enter the values on your calculator, you press MATH and move the cursor over to PRB and

find the nCr option

To find the answer for c:

Enter in the first number and then the nCr option after each number, placing the last number

afterward.

10 nCr 3

To find the answer for c:

Then when you have all the values put in your calculator, press enter and your answer is

given.

Since it is is decimal form, change it to a fraction.

0.4667 = 7/15

Question #4:

a) At the end of the three months, Sandra will owe $2950.87

b) If Sandra wants to pay it off in two years, her monthly payments will be $130.78

To find the answer for a:

The first step is to open up the TVM SOLVER on you calculator. Do this by pressing the APPS

button, then press enter on the finance application. And then press enter on the TVM

SOLVER.

To find the answer for a:

Once you have opened up the TVM SOLVER you should get a window that looks like this:

N = 0I%= 0PV= 0PMT= 0FV= 0P/Y= 1C/Y= 1PMT: END

To find the answer for a:

Once you have the TVM SOLVER opened you can start adding in the values

N = 60

I%= 18

PV= -1200

PMT= 0

FV= 2950.869

P/Y= 12

C/Y= 365

PMT: END

60 days of gathering interest

The amount of interest on the credit card

The present amount on her credit card

She isn’t making any payments yet and we aren’t looking for any

The answer for the future value on the card afterthe 60 days of gathering interest

The payments are calculated monthly

The money is compounded daily because it is a credit card

The payments are compounded at the end of the month

To find the answer for a:

Therefore the answer to a is that she will owe $2950.87 on her credit card at the end of the

three months.

To find the answer for b:

The first step is to open up the TVM SOLVER on you calculator. Do this by pressing the APPS

button, then press enter on the finance application. And then press enter on the TVM

SOLVER.

To find the answer for b:Once you have opened up the TVM SOLVER you

should get a window that looks like this:N = 0I%= 0PV= 0PMT= 0FV= 0P/Y= 1C/Y= 1PMT: END

To find the answer for b:Once the TVM SOLVER is open you can begin

adding in the values:N = 24I%= 6PV= 2950.869PMT= -130.784FV= 0P/Y= 12C/Y= 12PMT: END

24 months of gathering interest

The amount of interest added on through the bank

The price of the loan taken out

The monthly payments she will have to maketo pay off her loan

In the end she wants a future value of 0

The payments are calculated monthly

The money is compounded monthly

The payments are compounded at the end of the month

To find the answer for b:

Therefore the answer to b is that Sandra will have to make monthly payments of $130.78 to pay

off the loan in two years.

Question #5:

a)18.76%

b)86.31%

To find the answer for a:

The first step is to find the binomcdf function on your calculator.

Go 2nd VARS, and you will come to the DISTR screen, scroll down until you find the function.

To find the answer for a:

Now you can fill it in with the values:

binomcdf(200, 0.15,25)

To find the answer for a:

binomcdf(200, 0.15, 25)

We are looking at200 pieces of

jewelryOut of every box there

Is a probability 15% are broken

Outcome of exactly 25

To find the answer for a:

The you press enter to get the answer:

binomcdf(200, 0.15,25) = 0.1876

= 18.76%

To find the answer for b:

Since the binomial function calculates the probability from the outcome you are looking for right down to one, this question has one extra

step.

To find the answer for b:

Before you get the binomial function on your home screen, start off with this:

1 -

To find the answer for b:

Since we are looking for 25 or more, we will use the binomial function to find from 24 and down,

then subtract the value from one.

To find the answer for b:

We subtract from one because the values are given in percent form, and 1 will represent the

whole or 100%

To find the answer for b:

So your home screen should now look like this:

1 - binomcdf(200, 0.15, 24)

To find the answer for b:

Then press enter to get the answer:

1 - binomcdf(200, 0.15, 24) = 0.8631

= 86.31%

PHOTO REFERENCES:

www.flickr.com/photos/the-bh/389524779

www.flickr.com/photos/bee_cute_designs/2431999764

www.flickr.com/photos/7alawah/1169605983

www.flickr.com/photos/jafrph/2484740477

www.flickr.com/photos/maxivida/118691383

www.flickr.com/photos/rashdan/455195539

www.flickr.com/photos/janoid/389756903

www.flickr.com/photos/stacyrucker/2219760450

www.flickr.com/photos/destinyscreations/2423780363