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Recent problems solved by 'scott8148'

scott8148 answered: 6619 problems
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Mixture_Word_Problems/571243: By weight one alloy has 40% Aluminum, 38% Copper and the rest Cadmium. The second alloy has 52%, 20% and 28% Aluminum, Copper, and Cadmium respectively. The Aluminum, Copper, and Cadmium content of the third alloy is 61%, 12% and 27% respectively. How much of each alloy must be mixed to produce 1000 Lbs of alloy with the following content of 50.2% Aluminum, 23.8% Copper and 26% Cadmium? I am completely stumped on how to figure this one out. Can someone help Please? 1 solutions Answer 368040 by scott8148(6628)   on 2012-02-11 14:37:59 (Show Source): You can put this solution on YOUR website! let x = amount of 1st alloy , y = amount of 2nd alloy , and z = amount of 3rd alloy you are given the amounts of the components in the final alloy ___ Al = (50.2%)(1000) = 502 lb ___ Cu = (23.8%)(1000) = 238 lb ___ Cd = (26%)(1000) = 260 lb .4x + .52y + .61z = 502 .38x + .2y + .12z = 238 .22x + .28y + .27z = 260 solve the system of equations to find the amounts of the three alloys you might want to think about Cramer's Rule

Expressions-with-variables/571246: how do you solve -8x2+22x-5 1 solutions Answer 368038 by scott8148(6628)   on 2012-02-11 14:20:11 (Show Source): You can put this solution on YOUR website! factoring ___ (-4x + 1)(2x - 5)

Radicals/571247: Solve the equation for r. h= Vr^-2/3.14 I think I might have this figured out, but I'm not certain it is correct. Here is the final answer I got. r=(1/pie symbol*h)/V. All raised to the power of 2 1 solutions Answer 368037 by scott8148(6628)   on 2012-02-11 14:17:20 (Show Source): You can put this solution on YOUR website! h = V / (r^2 * pi) r^2 = V / (h * pi) r = sqrt[V / (h * pi)]

Radicals/571248: Suppose that a cylinder has a volume of 314 in^3 and a radius of 5 in. Find the height of the cylinder. Use pie symbol = 3.14. Here is the given equation,h= Vr^-2/3.14 I know we plug in 314in^3 for V and 5 for r, so h=3.14^3(5^-2)/3.14 The exponents are throwing me off with this equation....Please help me understand this, it is due today. Thank you 1 solutions Answer 368035 by scott8148(6628)   on 2012-02-11 14:12:01 (Show Source): You can put this solution on YOUR website! V = pi * r^2 * h 314 = 3.14 * 25 * h

Probability-and-statistics/571283: How do you find the smallest power of 0.917 that yields a value less than 0.10. The answer book says 27 (rounded up). How did they get that? 1 solutions Answer 368034 by scott8148(6628)   on 2012-02-11 14:07:24 (Show Source): You can put this solution on YOUR website! x log(.917) < -1

Complex_Numbers/571255: Please Help Me Solve : Write A Quadratic Function In Standard Form Of (-1,0) , (0,-5) , (2,3) 1 solutions Answer 368033 by scott8148(6628)   on 2012-02-11 14:05:15 (Show Source): You can put this solution on YOUR website! the general equation is ___ y = ax^2 + bx + c substituting the given points will form a system of equations that can be solved for the a, b, and c coefficients (-1,0) ___ (0) = a(-1)^2 + b(-1) + c (0,-5) ___ (-5) = a(0)^2 + b(0) + c (2,3) ___ (3) = a(2)^2 + b(2) + c

Proportions/571263: you have a total of 60 cupcakes; 36 are choc. You want 70% choc. How many more cupcakes do you need to bake ? 1 solutions Answer 368031 by scott8148(6628)   on 2012-02-11 13:33:36 (Show Source): You can put this solution on YOUR website! (36 + x) / (60 + x) = 70% 36 + x = 42 + .7x

Rate-of-work-word-problems/571268: Mary can finish an embroidery work in 10 days. After working for 3 days, Mary's cousin joined and together they finished the embroidery in another 4 1/2 days. How many days can Mary's cousin finish the work alone? 1 solutions Answer 368030 by scott8148(6628)   on 2012-02-11 13:30:39 (Show Source): You can put this solution on YOUR website! Mary worked for 7.5 days (3 + 4.5) and did 75% (7.5 / 10) of the job it took Mary's cousin 4.5 days to do 25% of the job

Rate-of-work-word-problems/571269: How much water should I evaporate from 10 liters of 3% salt solution if I want a solution containing 5% salt? 1 solutions Answer 368029 by scott8148(6628)   on 2012-02-11 13:26:52 (Show Source): You can put this solution on YOUR website! (3%)(10) = (5%)(10 - x)

Rate-of-work-word-problems/570872: Two cylindrical cans have the same volume. The height of one can is triple the height of the other. If the radius of the narrower can is 12 units, how many units are in the length of the radius of the wider can. I drew a picture to represent the 2 cans. I know that volume of can a=volume of can b. I know the height of can a=3b. I know the radius of can a is 12 units. I know the volume of a cylinder is pi (r)squared (h). I don't know what to do next. 1 solutions Answer 367845 by scott8148(6628)   on 2012-02-10 11:12:04 (Show Source): You can put this solution on YOUR website! pi * 12^2 * 3h = pi * r^2 * h dividing by (pi * h) ___ 12^2 * 3 = r^2

Graphs/570735: I've been trying to help my daughter, but it's been too long since I've done any algebra. She is currently in graphs, but this does not seem to fit. Anyway, here is the question posed. A rectangular hole 2cm wide and x cm long is cut in a rectangular sheet of metal 7/2cm wide and y cm long. The length of the hole is 1 cm less than the length of the metal sheet. After the hole is cut, the area of the remaining metal is 11cm squared. Find the length of the hole and the length of the metal sheet. I'm math stupid and having a difficult time trying to find help. Thank you for any suggestions, Jeff R. 1 solutions Answer 367746 by scott8148(6628)   on 2012-02-09 22:28:53 (Show Source): You can put this solution on YOUR website! "The length of the hole is 1 cm less than the length of the metal sheet" ___ x + 1 = y "After the hole is cut, the area of the remaining metal is 11cm squared" ___ (2*x) + 11 = (7/2)*y substituting ___ 2x + 11 = (7/2)(x + 1) ___ 2x + 11 = (7/2)x + (7/2) ___ 4x + 22 = 7x + 7 solve for x, then substitute back to find y

Triangles/570626: How do you find the area of a triangle with the sides 33,30 and 23. (I can NOT use Herons formula or the law of sine or cosines to find it btw. Its an extra credit problem and I need help : / 1 solutions Answer 367742 by scott8148(6628)   on 2012-02-09 22:18:50 (Show Source): You can put this solution on YOUR website! use the longest side as the base the altitude (h) divides the triangle into two right triangles; a, h, 30 and b, h ,23 a + b = 33 a^2 + h^2 = 30^2 b^2 + h^2 = 23^3 three equations, three unknowns subtracting 2nd and 3rd equations ___ a^2 - b^2 = 30^2 - 23^2 ___ (a + b)(a - b) = 371 dividing by 1st equation ___ a - b = 371 / 33 adding 1st equation ___ a - b + a + b = 33 + (371 / 33) ___ 2a = 1460 / 33 solve for a, then substitute back to find h

Geometry_Word_Problems/570613: this is a problem that my teacher gave me and no matter how I look at it it doesn't make any sense The perimeter of an equilateral triangle is 9 inches more than the perimeter of a square, and the side of the triangle is 6 inches longer than the side of the square. Find the side of the triangle. (Hint: An equilateral triangle has three sides the same length.) 1 solutions Answer 367740 by scott8148(6628)   on 2012-02-09 21:58:36 (Show Source): You can put this solution on YOUR website! "the side of the triangle is 6 inches longer than the side of the square" ___ t = s + 6 ___ t - 6 = s "The perimeter of an equilateral triangle is 9 inches more than the perimeter of a square" ___ 3t = 4s + 9 substituting ___ 3t = 4(t - 6) + 9 ___ 3t = 4t - 24 + 9

Finance/570702: Could someone please help me with this problem. There was an example in the book, but I didn't understand it. "An educational loan of $8400 for 10 years is to be repaid in monthly installments of $122.50. What is the annual rate of this loan, computed as simple interest?" 1 solutions Answer 367736 by scott8148(6628)   on 2012-02-09 21:47:01 (Show Source): You can put this solution on YOUR website! 10 years is 120 monthly payments find the total of the payments subtract 8400 to find the interest divide the interest by 10 to find the annual interest divide the annual interest by 8400 to find the percentage (interest rate)

Quadratic_Equations/570705: I need to solve : f(x)=(1)/(3) (x+4)^(2)+3 for the vertex, and the line of symmetry..Have been working on this one problem for about 20 minutes now. 1 solutions Answer 367732 by scott8148(6628)   on 2012-02-09 21:41:44 (Show Source): You can put this solution on YOUR website! the general vertex equation is ___ f(x) = a(x - h)^2 + k ; where (h,k) is the vertex so the axis of symmetry would be ___ x = h

Triangles/570584: How do i determine missing side lengths,of a triangle using the degrees of a triangle? 1 solutions Answer 367729 by scott8148(6628)   on 2012-02-09 21:38:15 (Show Source): You can put this solution on YOUR website! the "Law of Sines" states that the lengths of the sides of a triangle are in the same ratio as the sines of the angles opposite the sides side x is opposite angle X side y is opposite angle Y x / y = sin(X) / sin(Y)

Age_Word_Problems/570476: The sum of the present ages of Eric and his father is 65 years. In 8 years, his father will be twice as old as Eric will be at that time. Find their present ages. whats erics age? and whats erics dads age? 1 solutions Answer 367699 by scott8148(6628)   on 2012-02-09 18:15:29 (Show Source): You can put this solution on YOUR website! "The sum of the present ages of Eric and his father is 65 years" ___ E + f = 65 ___ f = 65 - E "In 8 years, his father will be twice as old as Eric will be at that time" ___ f + 8 = 2(E + 8) substituting ___ (65 - E) + 8 = 2E + 16 ___ 57 = 3E solve for E, then substitute back to find f

Word_Problems_With_Coins/570454: Suppose that Maria has 140 coins consisting of pennies, nickels, and dimes. The number of nickels she has is 15 less than twice the number of pennies; the number of dimes she has is 25 less than three times the number of pennies. How many coins of each kind does she have? (I have tried to translate into an equation, but it doesn't work. I had 2n-15 + 3n-25. I am not sure how to do this problem) 1 solutions Answer 367696 by scott8148(6628)   on 2012-02-09 17:07:20 (Show Source): You can put this solution on YOUR website! "140 coins consisting of pennies, nickels, and dimes" ___ p + n + d = 140 "The number of nickels she has is 15 less than twice the number of pennies" ___ n = 2p - 15 "the number of dimes she has is 25 less than three times the number of pennies" ___ d = 3p - 25 substituting ___ p + (2p - 15) + (3p - 25) = 140 ___ 6p - 40 = 140 solve for p, and then substitute back to find n and d

Rational-functions/570425: It takes 16 minutes to fill a tub with a stopper. It takes 20 minutes to empty a tub without a stopper. How long does it take to fill a tub without a stopper? 1 solutions Answer 367695 by scott8148(6628)   on 2012-02-09 17:00:53 (Show Source): You can put this solution on YOUR website! in the 16 min that it normally takes to fill, 4/5 (16/20) of the tub has drained so it takes 16 min to fill 1/5 of the tub

Linear-equations/569797: How can I turn 2y+6x=(-14) into slope intercept form and then find the slope and the y-intercept? 1 solutions Answer 367456 by scott8148(6628)   on 2012-02-08 16:41:50 (Show Source): You can put this solution on YOUR website! solve for y the general slope-intercept equation is ___ y = mx + b, where m is the slope and b is the y-intercept

Travel_Word_Problems/569778: if a car travels 90 km per hour, how far will it travel in 1 minute? im only in grade 5 so these questions might not be that challenging to you!:P:D 1 solutions Answer 367454 by scott8148(6628)   on 2012-02-08 16:38:55 (Show Source): You can put this solution on YOUR website! there are 60 minutes in an hour; so if you divide km per hr by 60, you get km per min 90 / 60 = ?

Equations/569716: A boat on a river travels downstream between two points, 60 mi apart, in one hour. The return trip against the current takes 2.5 hours. What is the boat's speed? ___mph How fast does the current in the river flow? ___ mph 1 solutions Answer 367446 by scott8148(6628)   on 2012-02-08 15:38:25 (Show Source): You can put this solution on YOUR website! b + c = 60 mi / 1 hr = 60 mph b - c = 60 mi / 2.5 hr = 24 mph adding equations ___ b + c + b - c = 60 + 24 ___ 2b = 84 ___ b = 42 substituting ___ (42) + c = 60 ___ c = 18

Trigonometry-basics/569237: ((cotA-cosA)(1+sinA)) all divided by cos^3A = cscA i am trying to simplify the left side to get it to equal the right. This is really urgent so any help right away would be GREATLY appreciated!!! Thanks 1 solutions Answer 367274 by scott8148(6628)   on 2012-02-07 19:28:00 (Show Source): You can put this solution on YOUR website! changing everything on left to sin or cos and FOILing cancelling cos(A) on the left ___ multiplying left side by [sin(A) / sin(A)] ___ ___ canceling cos^2(A) on the left side ___

Rational-functions/569246: when you have a number in front of x and y... how do you find the slope?? how do you find the x and y intercept in an easy way?? how do you graph an equation that is in standard form?? EXAMPLE: 3x+2y=6 how do you graph it?? 1 solutions Answer 367271 by scott8148(6628)   on 2012-02-07 18:24:09 (Show Source): You can put this solution on YOUR website! easy way for intercepts x equals zero at the y-intercept and y equals zero at the x-intercept take the standard form equation and ignore the term that your not finding the intercept of (because the term equals zero) 3x + 2y = 6 ___ ignoring the y-term ___ 3x = 6 ___ x = 2 ___ the x-intercept is (0,2) ignoring the x-term ___ 2y = 6 ___ y = 3 ___ the y-intercept is (3,0) graph the equation by locating the two intercepts and drawing the line through the two points the slope is also easy ___ -(y-intercept) / (x-intercept) ___ -3 / 2

Age_Word_Problems/568959: solve the equation the ages of a and b are in ratio 5:7.four years from now the ratio of their ages will be 3:4 . the present age of b is 1 solutions Answer 367254 by scott8148(6628)   on 2012-02-07 17:12:48 (Show Source): You can put this solution on YOUR website! 5b = 7a 3(b + 4) = 4(a + 4) ___ 3b + 12 = 4a + 16 ___ 21b + 84 = 28a + 112 subtracting 4 times first eqn ___ 21b + 84 - 20b = 28a + 112 - 28a ___ b = 28

Sequences-and-series/568967: write the first three terms of an arithmetic sequence if the fourth term is 10 and d=-3. 1 solutions Answer 367249 by scott8148(6628)   on 2012-02-07 16:59:33 (Show Source): You can put this solution on YOUR website! a + 3d = 10 a + 3(-3) = 10 ___ a - 9 = 10 ___ a = 19 19, 16, 13

Age_Word_Problems/568962: A man is 41 years old and his son is 9.In how many years will be the father be three times as old as his son? 1 solutions Answer 367246 by scott8148(6628)   on 2012-02-07 16:55:37 (Show Source): You can put this solution on YOUR website! f = 41 s = 9 f + x = 3(s + x) ___ 41 + x = 3(9 + x) ___ 41 + x = 27 + 3x ___ 14 = 2x

logarithm/568329: 10000e^(-0.06t) = 1000 Please help me solve for t :D 1 solutions Answer 366935 by scott8148(6628)   on 2012-02-06 09:08:03 (Show Source): You can put this solution on YOUR website! dividing by 10000 ___ e^(-0.06t) = 1/10 rules for exponents ___ e^(.06t) = 10 taking natural log ___ .06t = ln(10) dividing by .06 ___ t = [ln(10)] / .06

Pythagorean-theorem/568107: It is my 2nd day in my geometry class, I have switched from an online school & I have an upcoming test on slope/midpoint/distance. Im stuck on a question from the study guide because I was not there for the lessons. I need help ASAP! The question is: The length of a rectangle is three times as long as it is wide. If the length of the diagonal is 10sqrt6 feet, find the area of the rectangle. I cannot solve for this question no matter what I try! 1 solutions Answer 366853 by scott8148(6628)   on 2012-02-05 19:09:31 (Show Source): You can put this solution on YOUR website! if x is the width, then 3x is the length by Pythagoras ___ x^2 + (3x)^2 = [10sqrt(6)]^2 ___ x^2 + 9x^2 = 10^2 * [sqrt(6)]^2 10x^2 = 600 ___ x^2 = 60 the area is ___ x * 3x ___ or 3x^2 3(60) = 180

Word_Problems_With_Coins/567635: Hi I am trying to help my daughter with her math homework and I know the answer to the question but I am really not sure how I came up with it. Here is the question. Victor has 8 coins. He has 2 fewer dimes than nickels, and one more penny than nickels. How much money does he have? In my head I figured out that there is going to be 1 dime, 3 nickels, and 4 pennies and that would of course equal 29 cents. Unfortunately we have to explain our answer and show the work and that is where I am stuck. Thanks for your help! 1 solutions Answer 366651 by scott8148(6628)   on 2012-02-04 11:15:17 (Show Source): You can put this solution on YOUR website! "Victor has 8 coins" ___ p + n + d = 8 "He has 2 fewer dimes than nickels" ___ d = n - 2 "one more penny than nickels" ___ p = n + 1 substituting ___ (n + 1) + n + (n - 2) = 8 ___ 3n - 1 = 8 ___ n = 3 use the value of n to find p and d

Graphs/567462: y < 3x + 2 y >= -2x + 0 i have to get the solution i was given a hint: the point lays on line with the  equation;  y = -2 + 4x IT MAKES NO SENSE pliz help me :/ 1 solutions Answer 366572 by scott8148(6628)   on 2012-02-03 20:18:41 (Show Source): You can put this solution on YOUR website! why add zero? ___ is it a learning format thing...? plot the two lines ___ the < is dotted and the ≥ is solid ___ plot them like equations the lines will intersect and divide the graph into four zones pick a point in each zone and substitute the x and y values into the inequalities ___ only one zone will work in both ___ this is the solution ___ it is not a point, it is a zone