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Rational-functions/214606: Solve the equation for x. Round to two decimal places.
Please Show your work.
1. log[4](x)=3
2. In x=-2.5
3. 2*log[3](x)+4=1
4. 10*log(2x)=30
1 solutions

Answer 162059 by edjones(7569) on 2009-09-17 23:56:29 (Show Source):

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log[4](x)=3
4^log[4](x)=4^3
x=64
.
Ed

Probability-and-statistics/214419: 40) A newspaper advertises 5 different movies, 3 plays, and 2 baseball games for the weekend. If a couple selects 3 activities, find the probability that they attend 2 plays and 1 movie.
1 solutions

Answer 162058 by edjones(7569) on 2009-09-17 23:51:13 (Show Source):

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(5C1 * 3C2 * 2C0) / 10C3
=(5*3*1)/120
=15/120
=1/8
.
Ed

Money_Word_Problems/212064: If $1,000,000 of 8% bonds are issued at 102 1/2, the amount of cash received from the sale is _______. (Points: 4)
1 solutions

Answer 161492 by edjones(7569) on 2009-09-15 09:16:23 (Show Source):

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$1,025,000.

Geometry_Word_Problems/211958: Please help with this, I'm a lot lost with this one

During the last hour, a telemarketer dialed 25 numbers and reached 7 busy signals, 3 answering machines, and 15 people. Use this information to determine the empirical probability that the next call will be answered in person.
1 solutions

Answer 161490 by edjones(7569) on 2009-09-15 09:08:21 (Show Source):

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15/25=3/5 Probability

Travel_Word_Problems/209867: an airplane flew for 4 h 30 min at an average speed of 515 mi/h.how far did it fly?
1 solutions

Answer 161486 by edjones(7569) on 2009-09-15 08:55:56 (Show Source):

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time*speed=distance
4.5*515=2317.5mi
.
Ed

Travel_Word_Problems/213670: This question is from textbook The university of chicago school mathematics project
How long will it take a cheetah to run 100 yards at top speed which is 70 miles per hour.
1 solutions

Answer 161429 by edjones(7569) on 2009-09-14 21:38:15 (Show Source):

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1mi=1760yds
70*1760=123200yds
st=d
t=d/s
=100yds/123200yds/h
=1/1232 h
=(1/1232) / (1/60^2) Use 60^2 to convert from hrs to secs.
=(1/1232)*60^2
=2.922sec
.
Ed

Functions/213662: Find the domain of : y = sqrt(4x+1)
1 solutions

Answer 161420 by edjones(7569) on 2009-09-14 21:18:44 (Show Source):

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y = sqrt(4x+1)
4x+1<0 It can't be this because you can't do the square rout of a negative number.
4x<-1
x<-1/4
.
X(-1/4, infinity) The domain.
.
Ed

Equations/213658: xy = 11
xz = 4c
xz = 83
solve for c
1 solutions

Answer 161418 by edjones(7569) on 2009-09-14 21:07:48 (Show Source):

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4c=83 xz=xz
c=83/4
.
Ed

Volume/213650: Is it possible for a cone and a pyramid both of which have whole-number dimensions to have the same volume? Why or why not?
1 solutions

Answer 161414 by edjones(7569) on 2009-09-14 21:03:40 (Show Source):

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No, because a cone, since it contains pi will have an irrational number as its result and a pyramid since it contains only whole numbers will have only rational numbers for its result.
.
Ed

Exponents-negative-and-fractional/213643: factor by grouping
7t^2+35t-3t-15
1 solutions

Answer 161412 by edjones(7569) on 2009-09-14 20:56:29 (Show Source):

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7t^2+35t-3t-15
=7t(t+5)-3(t+5)
=(7t-3)(t+5)
.
Ed

Length-and-distance/213415: Hey there. the question is-
A 2m high fence lies 3m from a wall of abuilding. A ladder is placed on the other side of teh fence and just clears the fence to reach the wall.
i) Calculate the shorstest ladder that can be used to reach the wall, and just clearing the fence.
ii) Calculate the lenght of the ladder if its foot is 1m from the fence.
Thanks you so much. Great help!!
1 solutions

Answer 161197 by edjones(7569) on 2009-09-14 01:46:55 (Show Source):

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This question is about similar triangles. A question regarding similar triangles has been on every SAT test ever written.
a)
The ladder is the hypotenuse of a right triangle formed by the ground and the building wall as the other 2 sides. There is also a smaller similar triangle formed by the fence, ladder and ground.
The smallest possible hypotenuse (ladder) occurs when the triangles are isosceles (45 degree angles). (1,1,sqrt(2) triangle).
So, the length of ground from where the ladder touches to the fence must be equal to the height of the fence, 2m.
The distance from the ground to the wall is 5m and where the ladder touches the wall is also 5m.
The shortest length of the ladder is 5sqrt(2)m.
b)
If the ladder is 1 meter from the fence then the smaller triangle is a 1, 2, sqrt(5) triangle.
The distance to the wall is 4m. The ladder touches the wall at 8m high and the length of the ladder is 4sqrt(5)m.
.
Ed

Age_Word_Problems/213106: alice is twice as old as brian. cristal is three years younger then brian .the sum of their ages is 45. how old is cristal?
1 solutions

Answer 161004 by edjones(7569) on 2009-09-13 01:16:22 (Show Source):

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Let a=alice's age, b=brian's and c=crystal's
a=2b
c=b-3
.
b+2b+b-3=45
4b-3=45
4b=48
b=12
a=24
c=9
.
Ed

Age_Word_Problems/213108: a 43 foot long string is cut into 4 pices the first piece of string is twice as long as the second piece of string. the 3rd piece of string is 3 feet longer than the second pice of string the fouth piece is twice as long as the first piece.what is the length of thr longest piece of string/
1 solutions

Answer 161003 by edjones(7569) on 2009-09-13 01:09:52 (Show Source):

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Let the 1st piece=a, 2nd=b, 3rd=c and the 4th=d
a=2b
c=b+3
d=2a=2(2b)=4b
2b+b+b+3+4b=43
8b+3=43
8b=40
b=5
a=10
c=8
d=20
.
Ed

Angles/213111: The measure of the supplement of an angle is eighty more than the measure of the angle. Find the measure of both angles.
1 solutions

Answer 161002 by edjones(7569) on 2009-09-13 01:00:08 (Show Source):

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Let s=supplement and a=angle
s=a+80 for this angle
s=180-a for any angle
a+80=180-a (s=s)
2a=260
a=130 deg
s=50 deg
.
Ed

Graphs/213110: The measures of the angles of a pentagon are consecutive even integers. If the angles of a pentagon add up to 540 degrees, find the measure of each angle.
I have to set up a table with this problem also. I would really appreciate your help. Thanks for your time.
1 solutions

Answer 161001 by edjones(7569) on 2009-09-13 00:48:20 (Show Source):

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Let the angles be x, x+2, x+4, x+6, and x+8.
x+x+2+x+4+x+6+x+8=540
5x+20=540
5x=520
x=104 degrees
.
Ed

Miscellaneous_Word_Problems/213105: A hurricane strikes and a rural area is without food or water. Three crews arrive. One can dispense needed supplies in 13 hours, a second in 16 hours, and a third in 22 hours. How long will it take all three crews working together to dispense food and water?
1 solutions

Answer 160998 by edjones(7569) on 2009-09-13 00:41:06 (Show Source):

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1st crew does 1/13 of the work in 1 hr.
2nd crew does 1/16 of the work in 1 hr.
3rd crew does 1/22 of the work in 1 hr.
Together 1/13 + 1/16 + 1/22 = 176/2288 + 143/2288 +104/2288 = 423/2288 of the work in 1 hr. (2288 is the LCD)
2288/423=5.4... hrs it takes the 3 crews to do the job.
.
Ed

Travel_Word_Problems/212165: A boy can row a boat at a constant rate of 4 mi/hr in still water. He rows up-stream for 14 minutes and then rows downstream, returning to his starting point in another 12 minutes. Find the rate of the current.
1 solutions

Answer 160995 by edjones(7569) on 2009-09-13 00:25:07 (Show Source):

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Let c=speed of current
ts=d t=time, s=speed, d=distance
12(4+c)=14(4-c) Since the distances are equal.
48+12c=56-14c
26c=8
c=8/26=4/13 mph
.
Ed

Equations/213095: 3y/4-y/2=5
1 solutions

Answer 160990 by edjones(7569) on 2009-09-12 23:50:37 (Show Source):

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3y/4-y/2=5
3y-2y=20 multiply each side by 4.
y=20
.
Ed

Money_Word_Problems/212307: This question is from textbook college algebra
an investor has $5000 to invest for a period of 1 year. Find the range of per annum simple interest rates required to generate interest between $200 and $275 inclusive
1 solutions

Answer 160989 by edjones(7569) on 2009-09-12 23:48:47 (Show Source):

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Let x=interest rate.
5000x=200
x=200/5000
x=.04=4%
.
5000x=275
x=275/5000=.055=5.5%
.
Ans. between 4 and 5.5 percent inclusive.
.
Ed

Percentage-and-ratio-word-problems/213091: This question is from textbook Hutchinson, D., Bergman, B., & Baratto, S. (2005). Basic mathematical skills with geometry (6th ed.). Boston: McGraw-Hill.
Plywood comes in thickness of 5/8, ¾, ½ and 3/8 in. Which size is thickest?
1 solutions

Answer 160985 by edjones(7569) on 2009-09-12 23:34:41 (Show Source):

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3/4=6/8 the largest.

Equations/213092: 2n+3+4n=2n+5+4n-2
1 solutions

Answer 160984 by edjones(7569) on 2009-09-12 23:33:49 (Show Source):

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2n+3+4n=2n+5+4n-2
6n+3=6n+3
There is no answer.
.
Ed

Unit_Conversion_Word_Problems/212797: Children's Benadryl comes in syrup form. The label says to administer 5mg/kg body weight. The syrup contains 12.5mg/5ml. If the child weighs 44lbs, how many ml of syrup are contained in a dose?
1 solutions

Answer 160983 by edjones(7569) on 2009-09-12 23:32:11 (Show Source):

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44lbs=20 kg
5*20=100ml of syrup required.
.
Ed

Equations/212272: 3/4(x+2)=-1
1 solutions

Answer 160619 by edjones(7569) on 2009-09-11 00:42:32 (Show Source):

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3/4(x+2)=-1
x+2=-4/3 multiply each side by 4/3
x=-2- 4/3 subtract 2 from each side.
=-3 1/3 or -10/3
.
Ed

Numbers_Word_Problems/212288: write the verbal sentence as an equation or an inequity. Five less than the difference of twenty and a number x is less than or equal to fifty.
1 solutions

Answer 160618 by edjones(7569) on 2009-09-11 00:34:35 (Show Source):

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%2820-x%29-5%3C=50

Travel_Word_Problems/212335: The formula v2 = GM/r can be used to find the constant speed v of a satellite revolving around the earth ina circular orbit of radius r. G is a number known as the gravitational constant and M is the mass of the earth. Transform this formula to find the mass of the earth. I honestly have no idea what to do.
1 solutions

Answer 160617 by edjones(7569) on 2009-09-11 00:26:36 (Show Source):

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GM/r =v^2
M=rv^2/G Multiply each side by r/G
.
Ed

Polynomials-and-rational-expressions/212367: Why is it that there may be numbers that will not work? How do you know from your rational expression what numbers are not in the solution?
1 solutions

Answer 160616 by edjones(7569) on 2009-09-11 00:17:26 (Show Source):

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give an example.

Travel_Word_Problems/212375: Two bicyclists started at the same time from towns 84km apart and rode toward each other. Because one of them rode downhill, his speed was twice as great as that of the other. Find both speeds if they meet after two hours.
1 solutions

Answer 160615 by edjones(7569) on 2009-09-11 00:16:19 (Show Source):

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Let x=dist traveled by the slower bike.
2x+x=84
3x=84
x=28 mi
28mi/2h=14mi/h
28mi/h speed of the faster bike.
.
Ed

Polynomials-and-rational-expressions/212381: Can you please help me understand why and how to solve problems with parenthesis around it? Example: (-2) x 4 or -(-2) x (4)
Thank You
1 solutions

Answer 160613 by edjones(7569) on 2009-09-10 23:55:17 (Show Source):

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a negative times a negative is a plus.
(-2)*4
=-2*4
=-8
.
-(-2)*(4) The -(-2) is the same as -1(-2) which is the same as -1*-2
=2*4
=8
.
Ed

Geometry_Word_Problems/212392: Please help me answer: Width of a rectangle is fixed at 10cm. What lenths will amke the perimeter greater than 78cm.
1 solutions

Answer 160612 by edjones(7569) on 2009-09-10 23:49:22 (Show Source):

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Let L=length
2L+2w=P
2L+20>78
2L>58
L>29 cm
.
Ed

Polynomials-and-rational-expressions/212070: Please I need help with please!
1. √65+√21=
2.square root of 2 + square root of 18 =
3. sqrt(50) - sqrt(2)
1 solutions

Answer 160175 by edjones(7569) on 2009-09-09 02:47:00 (Show Source):

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1. sqrt(65)+sqrt(21) No easy way.
.
2.
sqrt(2)+sqrt(9*2)
=sqrt(2)+3(sqrt(2)
=4sqrt(2)
.
3.
sqrt(25*2)-sqrt(2)
=5sqrt(2)-sqrt(2)
=4sqrt(2)
.
Ed

Exponents-negative-and-fractional/211996: -x-3 x=-7
1 solutions

Answer 160173 by edjones(7569) on 2009-09-09 02:26:54 (Show Source):

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-x-3x=-7 Assuming this is the question
-4x=-7
x=7/4
.
Ed

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