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Tutors Answer Your Questions about Matrices-and-determiminant (FREE)
Question 604305: Hi! I think I got the correct answer to this word problem but am having trouble setting it up properly in a matrix (to get the right "output" answer). It is: when a crew rows with the current, it travels 16 miles in 2 hours. Against the current, the crew rows 8 miles in 2 hours. Let x=crew rowing rate in still water and y=rate of the current. I know rxt=d and x+y(t)=d and x-y(t)=d. I got x=6 and y=2. I have tried many different matrix "inputs" and just can't seem to get the right answer. I really wanted to figure it out on my own but am stuck. I know to line up the x's, y's, =k (constant). I need also to show the equation used.Thanks for any help!!!
Click here to see answer by ankor@dixie-net.com(15661)   |
Question 607392: An electronics company produces three models of stereo speakers, models A, B, and C, and can deliver them by truck, van or station wagon. A truck holds 2 boxes of model A, 1 of model B, and 3 of model C. A van holds 1 box of model A, 3 boxes of model B, and 2 boxes of model C. A station wagon holds 1 box of model A, 3 boxes of model B, and 1 box of model C. If 15 boxes of model A, 20 boxes of model B and 22 boxes of model C are to be delivered, how many vehicles of each type should be used so that all operate at full capacity?
I need help with setting up the equations for this problem. This is a matrix problem.
Is it something like this?
This is how I first translated it..
2x + 1y + 3z = truck
1x + 3y + 2z = van
1x + 3y + 1z = station wagon
Then I thought to maybe combine Boxes A, B, and C together within an equation:
Boxes A) 2x + 1y + 1z = 15
Boxes B) 1x + 3y + 3z = 20
Boxes C) 3x + 2y + 1z = 22
I'm a little lost.
Click here to see answer by ewatrrr(10682)  |
Question 607392: An electronics company produces three models of stereo speakers, models A, B, and C, and can deliver them by truck, van or station wagon. A truck holds 2 boxes of model A, 1 of model B, and 3 of model C. A van holds 1 box of model A, 3 boxes of model B, and 2 boxes of model C. A station wagon holds 1 box of model A, 3 boxes of model B, and 1 box of model C. If 15 boxes of model A, 20 boxes of model B and 22 boxes of model C are to be delivered, how many vehicles of each type should be used so that all operate at full capacity?
I need help with setting up the equations for this problem. This is a matrix problem.
Is it something like this?
This is how I first translated it..
2x + 1y + 3z = truck
1x + 3y + 2z = van
1x + 3y + 1z = station wagon
Then I thought to maybe combine Boxes A, B, and C together within an equation:
Boxes A) 2x + 1y + 1z = 15
Boxes B) 1x + 3y + 3z = 20
Boxes C) 3x + 2y + 1z = 22
I'm a little lost.
Click here to see answer by stanbon(57410) |
Question 607388: How much of a 40% antifreeze solution must a mechanic mix with an 80% antifreeze solution if 20 gallons of a 50% antifreeze solution are needed?
Here's what I tried:
Let x= amount of 40%, y= amount of 80%
0.40x + 0.80y = 0.5(20)
x + y = 20
Multiplied by 10 to get rid of decimals in first equation:
4x + 8y = 10
x + y = 20
Put into matrices and got:
(37.5, -17.5)
The answer is supposed to equal to 15 gal of 40%, 5 gal of 80% according to the lab worksheet I'm working on. I don't know what I am doing wrong.
Click here to see answer by ewatrrr(10682) |
Question 607390: $10,000 is to be invested in three different ways. One part of the money is used to purchase mutual fund that offer a return of 8% per year. The second part, which amounts to twice the first, is used to buy government bonds at 9% per year. The remainder is put in the bank at 5% annual interest. In the first year, the investments bring a return of $830. How much was invested in each way?
This is a matrices problem but I am confused with how to begin with the equations.
Is one equation x + y + z = 10,000? The second equation.. Is is something like this? 0.08x + 2(0.09)y =
I will be able to solve the problem after understanding how to put the wording into equations.. I understand how to solve matrices, so I am not asking for help with that. Thank you.
Click here to see answer by ankor@dixie-net.com(15661) |
Question 610864: Let U = {q, r, s, t, u, v, w, x, y, z}
A = {q, s, u, w, y}
B = {q, s, y, z}
C = {v, w, x, y, z}.
Determine whether the set is well defined. The set of rivers that flow south to north
Click here to see answer by jim_thompson5910(28598) |
Question 612685: solve using cramer's rule:
4x-3y=-7
3x-9y=15
x=?, y=?
i put these equations in the augmented matrix form, but i was stuck on how to actually solve the equation. i thought that you were only able to solve cramers rule if you are given a square matrix.
can you please help me solve this equation?
Click here to see answer by Alan3354(30993)  |
Question 615967: We're trying to help our soon with his math homework but we're totally stuck one this problem:
A store has a sale on almonds, pecans and pistachios. One lb of almonds, one lb of pecans and one lb of pistachios cost $12. Two lbs of almonds and three lbs of pecans cost $16. Three lbs of pecans and two lbs pistachios cost $24. Find the price of each kind of nut.
Thank you in advance for any help.
Click here to see answer by scott8148(6628)  |
Question 615967: We're trying to help our soon with his math homework but we're totally stuck one this problem:
A store has a sale on almonds, pecans and pistachios. One lb of almonds, one lb of pecans and one lb of pistachios cost $12. Two lbs of almonds and three lbs of pecans cost $16. Three lbs of pecans and two lbs pistachios cost $24. Find the price of each kind of nut.
Thank you in advance for any help.
Click here to see answer by Theo(3466)  |
Question 616252: I am havig difficulty determining the value of a determinant when there are fractions. Is there a short, easy way for me to evaluate? For example:
|3/4 3/4|
|1/16 -1/8|
I know the following:
(3/4)(-1/8)-(1/16)(3/4) = -3/32-3/64 = -9/64
what I cant explain is the numberator. Where is the -9 coming from? Please help!
Click here to see answer by dragonwalker(72) |
Question 618394: The Family Arts Center charges $22 for adults, $17 for senior citizens, and $6 for children under 12 for their live performances on Sunday afternoon. This past Sunday, the paid revenue was $13086 for 899 tickets sold. There were 47 more children than adults. How many children attended?
Click here to see answer by ewatrrr(10682) |
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