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#26 Re: Help Me ! » find the objective function » 2013-05-28 06:30:48

mom

Bob,

this problem is giving me a headache. My options are as follows:

A. -15x + 15y + 180

B. 45x + 65y

C. 105x + 105y

D. 5x + 5y + 1800

Please help

#27 Re: Help Me ! » Find the entry in the second row, first column of AB » 2013-05-28 05:47:58

mom

Bob,

nice! thanks so much for checking it for me.

#29 Re: Help Me ! » find the objective function » 2013-05-28 05:44:55

mom

Bob,

Here is another example:

STEP 1:  decide on the objective function, this is always going to be the function that is being maximized or minimized
STEP 2:  Set up the table, this will help with writing the constraints, later
STEP 3:  Write your constraints
If you have 42 hours available for assembly and each hockey game takes 2 hours and each soccer game takes 3 hours, then 2 times the number of hockey games assembled plus 3 times the number of soccer games assembled must be less than or equal to 42:
2x + 3y < 42


I was hoping that I used the correct data for the objective function. I pulled the data below from the problem:

If x represents the number of cars sent from Baltimore to Philadelphia and y represents the number of cars sent from New York to Pittsburgh, then what is the objective function?

It costs $45 to transport a car from Baltimore to Philadelphia, and $65 to transport a car from New York to Pittsburg.

To come up with:

45x+65y

There is a lot more data in the problem but the problem specified x for cars sent from Baltimore to Philadelphia and y for cars sent from New York to Pittsburgh. Therefore, I disregarded the data that didn't relate to x and y. I am just not sure if this is actually correct.

#31 Re: Help Me ! » Just want to make sure I am doing this correctly » 2013-05-28 05:31:03

mom

Bob,

yes they are two 3 x 3 matrices. So for the second row of AB it would be [15 1 2] ?

It didn't say to multiply so I wasn't sure that I worked the problem correctly but if you have A matrix B matrix and you have to come up with the second row of AB for the matrices, was I correct in assuming that I was to multiply?

Thanks so much.

#32 Re: Help Me ! » Just want to make sure I am doing this correctly » 2013-05-28 05:26:34

mom

Please see attached. I have never uploaded in here before but the attachment shows how I did my work.

I know how to go through the process of multiplication for the matrices. I am just not sure that is what the question was asking me to do.

#33 Help Me ! » find the objective function » 2013-05-28 04:54:45

mom
Replies: 20

Word problems are not my strong suite so if you could double check what I came up with it would be appreciated.

New cars are transported from docks in Baltimore and New York to dealerships in Pittsburg and Philadelphia. The dealership in Pittsburg needs 20 cars and the dealership in Philadelphia needs 15 cars. It costs $60 to transport a car from Baltimore to Pittsburgh, $45 to transport a car from Baltimore to Philadelphia, $65 to transport a car from New York to Pittsburg, and $40 to transport a car from New York to Philadelphia. There are 30 cars on the docks in Baltimore and there are 18 cars on the docks in New York. The number of cars sent from each dock to each dealership is chosen to minimize total transportation costs. If x represents the number of cars sent from Baltimore to Philadelphia and y represents the number of cars sent from New York to Pittsburgh, then what is the objective function?

What I got was 45x+65y

Is this correct or did I leave out some data that I shouldn't have?

#34 Help Me ! » System of equations equivalent to the matrix equation » 2013-05-28 04:46:13

mom
Replies: 2

I am used to doing this problem in reverse so I am hoping that I did it correctly.

Find the system of equations that is equivalent to the matrix equation given below.

[-2 5] [x] = [3]
[ 1 4] [y] = [6]

The answer that I got was {-2x+5y=3
                                       {   x+4y=6


Did I do this correctly?

#35 Help Me ! » Find the entry in the second row, first column of AB » 2013-05-28 04:41:06

mom
Replies: 2

Please let me know if I did this correctly.

I have Let A = [1 4] and B = [3 -2]. find the entry in the second row, first column of AB.
                       2 3                4  6

I multiplied A and B to get AB and the number I got for the second row, first column of AB was 18. Did I do this correctly?

#36 Help Me ! » Just want to make sure I am doing this correctly » 2013-05-28 04:37:39

mom
Replies: 6

I have:
Let A=[-2 1 3] and B = [0 1 -3]. Find the second row of AB.
            1 0 5                1 3 -4
            0 4 2                3 0  1

I multiplied and for the second row of AB, I got [15 1 2]

Is this correct?

#38 Help Me ! » Please help with the process on how to work this out » 2013-05-22 02:57:20

mom
Replies: 1

Is it more profitable to receive $2000 now or $3500 in 10 years?  Assume that money can earn 6% interest compounded monthly.

#39 Help Me ! » amount to deposit » 2013-05-21 03:29:57

mom
Replies: 10

How much money would have to be deposited now at 4.5% interest compounded monthly to accumulate to $6500 in 4 years?

Could someone please show me how to work this one? Which formula is it that I use?

#41 Re: Help Me ! » the abreviation of the indicated operation » 2013-05-20 08:13:59

mom

it is row and it is subscript for the indication. i just dont know how to do that in here
thank you

#42 Help Me ! » the abreviation of the indicated operation » 2013-05-20 07:19:44

mom
Replies: 4

I have the following:

1/2 x - 4y = 5
4x + 7y = 2

I am told to multiply the first equation by -2

the transformed system is

-1x + 8y = -10
4x + 7y = 2

What is the abbreviation of the indicated operation? _R
                                                                               _

Im stuck. Please help

Is it -2R
            1

#43 Re: Help Me ! » Find the equation » 2013-05-15 09:24:33

mom

that was actually supposed to be y=-2x-3
find the equation of the line passing through the point (-2, 5) and parallel to y=-2x-3

y=-2x+1
y=-2x+3
y=-1/2x+4
y=2x-1

#44 Re: Formulas » fixed cost » 2013-05-15 09:15:08

mom

wow!! not sure qhat i did wrong on that one

#45 Re: Formulas » line intersections » 2013-05-15 09:12:12

mom

confusing quwstion
thanks

#48 Re: Formulas » equation describing the same line » 2013-05-15 05:04:29

mom

I worked it out again and got it. Thanks so much

#49 Re: Formulas » fixed cost » 2013-05-15 05:02:33

mom

Then I am doing something incorrectly because I am coming up with y=30x+1310 and that is not one of my options.

#50 Re: Formulas » y-intercept » 2013-05-15 05:00:31

mom

thank you. I see what I did wrong.

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