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edjones answered: 7568 problems
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Surface-area/253325: A certain set contains three triangles: scalene, isosceles, and equilateral. If a triangle is selected at random, what is the probability that at least one of its medians is also an altitude? (1) 0 (3) 2/3 (2) 9 (4) 1 1 solutions Answer 185836 by edjones(7569)   on 2010-01-04 13:10:48 (Show Source): You can put this solution on YOUR website! Median: A line segment drawn from one vertex to the midpoint of the opposite side. 2/3 Scalene is the exception. . Ed

Expressions-with-variables/253516: Express 0.01 as a fraction. Show all work. PS Thanks to all for this great web site. I am taking an Algebra coorespondance course and am almost done, finding this site will allow me to complete the few problems and finish assignments! 1 solutions Answer 185833 by edjones(7569)   on 2010-01-04 13:01:25 (Show Source): You can put this solution on YOUR website! 1/100

Rational-functions/253355: Which of the following is a horizontal asymptote of f(x)= 1/x^2-16? a. x=-4 b. y=4 c. x=1 d. y=0 1 solutions Answer 185719 by edjones(7569)   on 2010-01-04 00:46:24 (Show Source): You can put this solution on YOUR website! Since The exponent of x is greater in the denominator then the horizontal asymptote is at y=0 . Ed .

logarithm/253368: All logs are base 12 Logx=.5log9+1/3log27 I got 49.5, I'm just wondering if it's right. THANKS! 1 solutions Answer 185714 by edjones(7569)   on 2010-01-04 00:26:28 (Show Source): You can put this solution on YOUR website! All logs are base 12 log(x)=.5log(9)+1/3log(27) log(x)=log(3)+log(3) [log(sqrt of 9) + log(cube root of 27)] log(x)=log(9) x=9 This answer is the same no matter what base is used and you don't have to convert any logs to get the answer! . Ed

Age_Word_Problems/253371: if i took away two years from my age and gave them to my sister she be twice my age well why don't i take just one more year off mine and put it on my sister. That makes her three times my age? what is the age of each person 1 solutions Answer 185709 by edjones(7569)   on 2010-01-04 00:00:11 (Show Source): You can put this solution on YOUR website! Let m=my age & s=sister's age . 2(m-2)=s+2 3(m-3)=s+3 . 2m-4=s+2 3m-9=s+3 . 2m-s=6 3m-s=12 ---------------subtract -m = -6 . m=6 s=6 . Ed

logarithm/253372: 5^2x=8 1 solutions Answer 185707 by edjones(7569)   on 2010-01-03 23:45:52 (Show Source): You can put this solution on YOUR website! 5^(2x)=8 log[5](5^(2x))=log[5](8) 2x=log[5](8) 2x=1.292 x=.646 . Ed

logarithm/253374: 3e^-x=18 1 solutions Answer 185706 by edjones(7569)   on 2010-01-03 23:39:50 (Show Source): You can put this solution on YOUR website! 3e^-x=18 e^-x=6 ln(e^-x)=ln(6) -x=ln(6) -x=1.7918 x=-1.7918 . Ed

Probability-and-statistics/253425: In a word game, you choose a tile from a bag, replace it, and then choose another. If there are 28 vowels and 16 consonants. what is the probability you will choose a consonant and then a vowel? 1 solutions Answer 185705 by edjones(7569)   on 2010-01-03 23:33:01 (Show Source): You can put this solution on YOUR website! 28+16=44 16/44 * 28/44 =.2314 probability . Ed

Linear-systems/253391: for y=3|7-2x| + 5, which set describes x when y<8? A. {x|3 B. {x|3 C. {x|x<3 or x>4} D. {x|x<3 or x> 10} 1 solutions Answer 185702 by edjones(7569)   on 2010-01-03 23:27:28 (Show Source): You can put this solution on YOUR website! 3|7-2x| + 5 < 8 3|7-2x|<3 |7-2x|<1 . 7-2x<1 -2x<-6 x>3 reverse inequality sign . 7-2x>-1 reverse inequality sign and 1 becomes negative. -2x>-8 x<4 reverse inequality sign . A. 3

Polynomials-and-rational-expressions/253397: simplify: 1/x+1 ------ 1/x-1 1 solutions Answer 185698 by edjones(7569)   on 2010-01-03 23:15:58 (Show Source): You can put this solution on YOUR website! . = . = . Ed

Polynomials-and-rational-expressions/253402: if the domain of f(x)=4x^2-4x-2 is (-7,-5,-3,-1,1,2,3,4,6) what is the range ? 1 solutions Answer 185696 by edjones(7569)   on 2010-01-03 23:04:28 (Show Source): You can put this solution on YOUR website! f(x)=4x^2-4x-2 The domain is all real numbers, not the numbers listed above. -a/2b=4/8=1/2 (x at the minimum) If a is positive it has a minimum. 4(1/2)^2-4(1/2)-2 =1-2-2 =-3 (y at the minimum) The range is (infinity to -3] . Ed .

Probability-and-statistics/253419: two fair number cubes numbered 1 through 6 are tossed, what two sums are least likely to occur? explain your answer 1 solutions Answer 185690 by edjones(7569)   on 2010-01-03 22:48:45 (Show Source): You can put this solution on YOUR website! There are 36 different possibilities of numbers from 2 to 12. 1 & 1 = 2 occur only one way as does 6 & 6 = 12 Answer 7 can occur 6 ways: 1 6, 6 1, 2 5, 5 2, 3 4 & 4 3. . Ed

logarithm/253375: log2 4x = log2 12 1 solutions Answer 185687 by edjones(7569)   on 2010-01-03 22:43:12 (Show Source): You can put this solution on YOUR website! log2 4x = log2 12 2^(log2 4x) = 2^ (log2 12) 4x=12 x=3 . Ed

Rectangles/253415: 4. If the perimeter of a rectangle is 8√2 cm, what is the smallest possible value of the length of one of its diagonals in cm? I've tried: let length be l, width be w, and diagonal be d let l be x, then w will be: (8√2-2x)/2 = 4√2-x d^2=l^2+w^2 =x^2+(4√2-x)^2 =x^2+(32-8√2x-x^2) =32-8√2x... 1 solutions Answer 185686 by edjones(7569)   on 2010-01-03 22:39:22 (Show Source): You can put this solution on YOUR website! A square has the smallest possible diagonals. s=8sqrt(2)/4 =2sqrt(2) One side of the square a^2+b^2=c^2 2sqrt(2)^2 + 2sqrt(2)^2 = c^2 8+8=16 c=4 cm . Ed

Inverses/253238: A certain kind of animal weighs about 77 pounds at birth and gains about two pounds per day for the first few weeks. Determine the days for which the animal's weight is more than 129 pounds. 1 solutions Answer 185516 by edjones(7569)   on 2010-01-03 13:49:00 (Show Source): You can put this solution on YOUR website! let d=number of days. 77+2d>129 2d>52 d>26 . Ed

Linear-systems/253240: I have an equation that has x over 2, like this: y=x/2 Is it the same as 1/2x? 1 solutions Answer 185511 by edjones(7569)   on 2010-01-03 13:44:52 (Show Source): You can put this solution on YOUR website! Same as (1/2)x Writing 1/2x incorrect and confusing. Use parentheses or x/2 to avoid confusion. . Ed

Linear-systems/253239: I have these two equations: 1/3x+y=1 and -4x+y=1 I have to solve it using elimination. What do I do to isolate a single variable? 1 solutions Answer 185508 by edjones(7569)   on 2010-01-03 13:40:05 (Show Source): You can put this solution on YOUR website! 1/3x+y=1 -4x+y=1 . 1/3x=-4x Since either number added to y equals 1. 1=-12x^2 x^2=-1/12 x=+-sqrt(1/12)i =+-sqrt(1/3)/2 *i x=sqrt(1/3)/2 *i, -sqrt(1/3)/2 *i . Ed

Graphs/253233: Simplify: (-3b^5)(2bc^2) 1 solutions Answer 185502 by edjones(7569)   on 2010-01-03 13:25:03 (Show Source): You can put this solution on YOUR website! -6b^6c^2

Polynomials-and-rational-expressions/253210: Another word problem! A six passenger plan cruises at 180 mph in calm air. If the plane flies 7 miles with the wind in the same amount of time as it flies 5 miles against the wind, then what is the wind speed? 1 solutions Answer 185489 by edjones(7569)   on 2010-01-03 12:57:50 (Show Source): You can put this solution on YOUR website! Let w=wind speed, s=speed, d=distance, t=time s/d=t (s+w)/7 = (s-w)/5 5(180+w)=7(180-w) 900+5w=1260-7w 12w=360 w=30 mph . Ed

Triangles/253145: please explain why its possible to have an isosceles right triangle but not an equilateral right triangle 1 solutions Answer 185392 by edjones(7569)   on 2010-01-02 22:53:53 (Show Source): You can put this solution on YOUR website! An equilateral right triangle would have three 90 degree angles. The sum of the angles of a triangle is always 180 degrees. . Ed

Surface-area/253147: what is the volume of a cube with an edge length of 4 inches? 1 solutions Answer 185390 by edjones(7569)   on 2010-01-02 22:49:13 (Show Source): You can put this solution on YOUR website! 4^3=64 in^3

Triangles/253146: Tim says that if the measure of one angle of an isosceles triangle equals 30 degrees, then the measure of the other two angles must each be 75. Marc disagrees he says that while Tim is correct some of the time, there is another possible solution.support Tim's claim and Marc's claim.explain how the angle measures where found please. 1 solutions Answer 185389 by edjones(7569)   on 2010-01-02 22:47:06 (Show Source): You can put this solution on YOUR website! There are 2 possibilities: 30+75+75=180 30+30+120=180 . Ed

Probability-and-statistics/250452: Truck tire life is normally distributed with a mean of 60,000 miles and a standard deviation of 4,000 miles. What is the probability that the tire will last 72,000 miles or more? a. .0013 b. .9987 c. .4987 d. .9544 1 solutions Answer 185112 by edjones(7569)   on 2010-01-01 17:21:01 (Show Source): You can put this solution on YOUR website! a

Probability-and-statistics/250451: mileage tests were conducted on a randomly selected sample of 100 newly developed automobile tires. The average tread wear was found to be 50,000 miles with a standard deviation of 3,500 miles. What is the best estimate of the average tread life in miles for the population of these tires? a. 50,000 b. 3,500 c. 50,000/100 d. 3,500/100 1 solutions Answer 185111 by edjones(7569)   on 2010-01-01 17:18:55 (Show Source): You can put this solution on YOUR website! a

absolute-value/249546: solve |12+4x|-6=26 16≤24-8x/5 |3x-9|>12 3|1-4x|+4≤28 1 solutions Answer 185024 by edjones(7569)   on 2010-01-01 11:52:19 (Show Source): You can put this solution on YOUR website! 3|1-4x|+4<=28 3|1-4x|<=24 |1-4x|<=8 . 1-4x<=8 -4x<=7 x>=-7/4 reverse the inequality sign when * or / by a negative number. . 1-4x>=-8 reverse the inequality sign and make the 8 negative. -4x>=-9 x<=9/4 reverse the inequality sign again. . Ed .

Inequalities/252882: If n < 0, which of the following could be true? I. 2n < n^2 II. 2n < n III. n^2 < – n (A) None (B) I only (C) I and II only (D) I and III only (E) I, II, and III 1 solutions Answer 185018 by edjones(7569)   on 2010-01-01 11:24:33 (Show Source): You can put this solution on YOUR website! Let n=-2 I. -4<4 true II. -4<-2 true III. 4< 2 false Answer: C . Ed

Numbers_Word_Problems/252879: the question is Show the conjecture is false by finding a counterexample the difference of two numbers is less than the greater number. 1 solutions Answer 184986 by edjones(7569)   on 2010-01-01 02:33:09 (Show Source): You can put this solution on YOUR website! 10-(-2)=12

Coordinate-system/252861: which two equations represent perpendicular lines. (a) y = 2/3 x – 3 (b) y = 3x – 2/3 (c) y = -1/3x + 2/3 (d) y = 1/3x – 2/3 1 solutions Answer 184970 by edjones(7569)   on 2009-12-31 19:28:39 (Show Source): You can put this solution on YOUR website! b & c. One is the negative reciprocal of the other.

Coordinate-system/252862: which two equations represent parallel lines. (a) y = –7x + 4 (b) y = 7x + 4 (c) y = x + 4 (d) y = –7x + 5 1 solutions Answer 184969 by edjones(7569)   on 2009-12-31 19:24:07 (Show Source): You can put this solution on YOUR website! a & d. Both have the same slope -7

Probability-and-statistics/252818: A student takes a multiple choice exam with 10 questions, each with four possible selections for the answer. A passing grade is 60% or better. Suppose that the student was unable to find time to study for the exam and just guesses at each question. Find the probability that the student a. gets at least one question correct b. passes the exam c. receives an "A" on the exam (90% or better) d. How many questions would you expect the student to get correct? e. Obtain the standard deviation of te number of questions that the student gets correct 1 solutions Answer 184951 by edjones(7569)   on 2009-12-31 16:12:00 (Show Source): You can put this solution on YOUR website! Except for question e) these can be figured out by expansion of a binomial. Let r = .25 probability of getting question right. and w = .75 prob getting it wrong. (r+w)^10 since there are 10 questions will tell us what we want to know. a) 1-w^10 doesn't get them all wrong. 1-.75^10 =1-.0563 =.9437 . b) 6-10 answers right r^10+10r^9w+45r^8w^2+120r^7w^3+210r^6w4 =.0197 . c) 9 or 10 right r^10+10r^9w =.00003 . d) 10 * .25 = 2.5 expected correct answers. . e) Standard deviation for a binomial distribution is sqrt(n*p(1-p)) =sqrt(10*.25*.75) =sqrt(1.875) =1.369 . Ed

Equations/252829: One of two positive integers is 8 more than the other. If the product of the two integers is 84, find the integers. Must be solved in an algebraic solution. 1 solutions Answer 184945 by edjones(7569)   on 2009-12-31 15:23:01 (Show Source): You can put this solution on YOUR website! Let the numbers be x and x+8 x(x+8)=84 x^2+8x-84=0 (x+14)(x-6)=0 x=6, x+8=14 . Ed