Tutors Answer Your Questions about Linear Algebra (FREE)
Question 66175: I'm not sure if this is Linear Algebra, but i have a good feeling. So:
Suppose Y varies directly with the square of W and the cube of X. When W=4 and X=2, Y=72. Find Y when W=1 and X=5.
I'm having problems setting the problem up and I don't know what it means when it says it varies directly with the (square, cube, etc..) of X (or whatever).
Much appricated thanks!
Click here to see answer by stanbon(57984)  |
Question 66263: MS.SPEEDI IS PLANNING ON STARTING AT THE FINISH LINE AND WALKING TOWARD THE STARTING LINE WHEN THE RACE STARTS.IF SHE WALKS ONE METER PER SECOND AND MEETS DINA 11 SECONDS AFTER THE START OF THE RACE,HOW LONG IS THE RACE?
Click here to see answer by stanbon(57984) |
Question 66699: What is wrong with this arguement? Suppose x and y represent two real numbers, where x > y
2 > 1
2(y-x)> 1(y-x)
2y-2x>y-x
y-2x>-x
y>x
The final inequality, y>x, is impossible because we were initally given x>y.
Extra info in problem possibly the "arguement"...This is a true statement . Multiply both sides by y-x. Use the distribtive property . Subtract from both sides. Add 2x to both sides.
Click here to see answer by Nate(3500) |
Question 67291: A teacher gives a final exam and the scores range from 40 to 80. The teacher decides to scale the exam in order to make the scores range from 60 to 90. Let x represent the original score and let y represent a converted score.
What will the original score of 45 become? Round the answer to the nearest whole number.
Click here to see answer by stanbon(57984) |
Question 67792: A farmer normally plows a rectangular field 80ft by 120 ft. This year the farmer wants to expand the area of the field by 20%, by extending the width and length of the plowed area an equal amount. How much wider and longer should the farmer plow the field to obtain a 20% increase in area?
Click here to see answer by ankor@dixie-net.com(15747)  |
Question 67792: A farmer normally plows a rectangular field 80ft by 120 ft. This year the farmer wants to expand the area of the field by 20%, by extending the width and length of the plowed area an equal amount. How much wider and longer should the farmer plow the field to obtain a 20% increase in area?
Click here to see answer by checkley71(8403) |
Question 67901: My math problem is broken up into check points in my book.
Check point 1) A company manufactures bookselves and desks for computers. Let x represent the numbers of bookselves manufactured daily and y the number of desks manufactured daily. The company's profits are $25 per a bookshelf and $55 per desk. Write the objective function that describes the company's total profit, z, from x bookselves and y desks.
Check point 2) To maintain high quality, the company in check point 1 should not manufacture more than a combined total of 80 bookselves and desks per day. Write an inequality that describes this constraint.
Check point 3) To meet consumer demand, the company in check point 1 must manufacture between 30 and 80 bookselves per day, inclusive. Furthermore, the company must manufacture between 10 and no more than 30 desks per day. Write an inequality that describes each of these sentences. Then summarize what you have described about this company by write the objective function for it's profits, and the three constraints.
Check point 4) For the company in check points 1-3, how many bookselves and how many desks should be manufactured per day to obtain a maximum profit? What is the maximum daily profit?
Click here to see answer by stanbon(57984) |
Question 67939: Most three-way light bulbs have only two filaments. The first filament may be 50 watts, for example. The second filament may be 100 watts. The three levels of brightness are obtained by using the first filament(50 watts), the second filament (100 watts), or both filaments together(150 watts). Unfortunately, your eye won't see these three steps as changes that lead to equal ratios of brightness. Switching from the first to second level yielddsd a brightness ratio of 100:50, or 2:1. However, going from the second to third level yields a ratio of 150:100, or 3:2. The two ratios are not equal.
Suppose you are asked to design a tree-way lightbulb that has a 50-watt element as its first filament , and yields equal ratios for 2nd level/1stlevel and
3rd level/2nd level.
let x be the wattage of the second filament. then the brightness of the third level will be x+50, and you want the following relationship:
2ne level / 1st level = 3rd level/2nd level
or
x /50 = x+50/x
a. Determine twhat wattage (x) should be used for the 2nd filament to meet the desired conditions.
b. Check the results of part A. What is the ratio of 2nd to 1st filament wattage? What is the ratio of 3rd to 2nd? Do they match?
c. Suppose the 1st filament is only 40 watts. what would that wattage of the 2nd filament need to be?
Click here to see answer by stanbon(57984) |
Question 68693: state the slope and y-intercept of the graph of each equation.
3. y=2/3x
6. 3x-24+6=0
weite an equation in slope-intercept form for the line that satisfies each set of conditions.
12. slope 3, passes through (1,3)
15. slope 3, passes through (2,0)
Click here to see answer by rmromero(383) |
Question 68693: state the slope and y-intercept of the graph of each equation.
3. y=2/3x
6. 3x-24+6=0
weite an equation in slope-intercept form for the line that satisfies each set of conditions.
12. slope 3, passes through (1,3)
15. slope 3, passes through (2,0)
Click here to see answer by checkley71(8403) |
Question 68693: state the slope and y-intercept of the graph of each equation.
3. y=2/3x
6. 3x-24+6=0
weite an equation in slope-intercept form for the line that satisfies each set of conditions.
12. slope 3, passes through (1,3)
15. slope 3, passes through (2,0)
Click here to see answer by mara2008(1) |
Question 70454: Word problem.
With a head wind, a plane traveled 840 miles northward in 2 hours. With the same wind as a tail wind, the return trip southward took 1 hour and 45 minutes. Find the plane's air speed and the wind speed
Click here to see answer by checkley75(3666) |
Question 71533: These are more about problem solving with equations
7)A jet plane traveling at 500 mph overtakes a propeller plane traveling at 200 mph that had a 2 hour head start. How far from the starting point are the planes?
9) The jones family drove to Disneyland at 50 miles per hour and returned on the same route at 40 mph. Find the distance to Disneyland if the total time was 7.2 hours?
11) How much pure acid should be mixed with 2 gallons of a 40% acid solution in order to get a 70% acid solution?
13)Planters peanuts company wants to mix 20 pounds of peanuts worth $3 a pound with cashews worth $5 a pound in order to make an experimental mix worth $3.50 a pound. How many pounds of cashews should be added to the peanuts?
Click here to see answer by ankor@dixie-net.com(15747) |
Question 72047: i understand this is a free site, but i have sent the same problem in twice today got a response and then i needed to know how they got part of the problem.
i have only wrote in on three problems. is that a problem?
Click here to see answer by bucky(2189) |
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