Posts by Dr. Jane
Total # Posts: 512

Statistics
You have to find the zscore for both 50 and 70 minutes. Change the 1.02 hours to 61.2 minutes for the mean. z = (50 61.2)/9 do the same for the 70 minutes. go to a standard ztable and find the area between those two values. Do the same thing for B. Your mistake was not ... 
Math
Use the formula that I gave you in the previous post. 
Math
Area of a Triangle = 1/2 x b x h If your units are the same then just enter them into the formula. 
math
See the one I just did. Here, you will have to change 960 m to mm 1000 mm = 1 meter 
math
First change cm to mm 350 cm = 3500 mm Area = L x W 3500mm = L(50mm) Divide to solve for L 
statstics
Check the links below. I answered this one last night. 
math 7
There are 24 marbles 16 are either green or red 16/24 reduce to get the probability. 
Math
(90, 220) and (76, 178) You have two points, so you can write an equation of a straight line in the form or y = mx + b First find the slope: m =(220178)/(9076) Once you have the slope. Use it and one of the points to find the equation of the line. To interpret the slope the ... 
quick math
12 x 14 =168 square feet. If the pavers were 1 foot by 1 foot we would need 168 pavers BUT.. your paver is 8 inches which is 8/12 or 2/3 of a foot. It is 2/3 times 2/3 or 4/9 square ft 168 divided by 4/9 which is the same as 168 times 9/4 That will get you to 378. 
algebra
John's distance = 10t Fred's distance = 12t John + Fred distance = 55 so 55 = 10t + 12 t You can find time in hours by solving the equation. 
math
for the second one you have b^2 under a radical sign with an index of 3 (or root of 3) You have some typos in the first one.. but if I am a reading it correctly. (w+9)^3 = 56 take the cube root of both sides w + 9 = cube root of (56) subtract 9.. the 9 will not be under the ... 
stats
You are looking for reduced speeding. I am assuming "md" indicates the mean of the difference. Ho is correct by H1 should be md<0 Be sure you subtract in the correct way. after  before = less than zero Use the formula for the ttest for dependent samples (... 
math help please ASAP
This isn't math... probably the science people won't look at it. This looks like biology to me. 
math
You can change both fractions to 20ths and then compare the fractions. 4/5 multiply by 4/4 2/4 multiply by 5/5 
Math (algerba 1)
Law of exponents says that you can distibute your power to when multiplying so you would have 4^2 x 10^10 I multiplied the two powers.. 4^*1*2) x 10^(5*2) 16 x 10^10 I don't know if your teacher wants you to write this in a different form or not. If could be 1.6 x 10^9 
pre algebra
Is this (x  7) divided by (7x  9)? 
math
You are welcome. 
math
Perimeter = L + L + W + W or P = 2L + 2W L = 5+ 2w P = 2(5+2W) + 2W I replaces the L in the original formula with the 5 + 2w because that equals L according to the problem. 34 = 10 + 4W + 2W Just solve for W. And then you can find L. 
math
Which fraction is larger? Since the denominators are the same, just compare the numerators. 
Math, Fraction
1/6 times 30 = 5 pennies 1/5 times 30 = _____ nickels 1/3 times 30 = _______dimes Add up your coins and subtract from 30 to find the number of quarters. 
math
I did this a minute ago. 
math
3/12 Reduce this fraction to lowest terms. 
maths
Here are a couple examples for you 567,000 in scientific notation is 5.67 x10^5 You always have one number in fron to the decimal place (in the ones place) multiplied 10. If you need to make the number larger the exponet on the 10 is positive. If you need to make the number ... 
math
19/38 reduce to lowest terms as a fraction or express as a decimal 
Math
For the ribbon problem 98  12(5) = length of ribbon. 
Math
Sam ate 1/4 of 8 is 1/4 x 8 = 2 slices There are 6 slices left. 
Math
This should be 3/4 of 12 or 3/4 times 12 = 9 sections 
Statistics
90% confidence interval indicates that 90% of the confidence intervals that you form using the same procedure will contain the true mean of the population. You had a sample and you are trying to predict the mean response from the total population. That is why we create a ... 
Physics 11
You are welcome. 
Physics 11
The second man is travelling for 2 seconds. The first man is travelling for 3 seconds. acceleration due to gravity = 9.8m/sec^2 d = vt v = at we can combine to get d =at^2 a in this case is g. You can find the distance of each jumper and find the difference. 
math
1. you have to add 4 to each part of the inequality and then divide by 4. That will cause the same reversal as above. Be careful with that final answer. 2. Multiply each part by 1 25>x>10 You have to turn this around for your final answer.. Like we did above. 
math
For the first one just add 7 to each part of the inequality. that will leave x alone in the middle. For the second one, this gets a little tricky. You have to divide each part of the inequality by 12. Whenever you multiply or divide and inequality by a negative number you ... 
math
You cannot simplify if you have a sum of x + y under a square root. if you have xy under a square root, you can write it as square root of x times the square root of y. 
maths
You can do this the same way that you would factor x^2  x  90 But.. this time we have x^4 and x^2 (x^2 10)(x^2 +9) 
Math
Another approach is to use: y = mx + b You will have m, x and y. solve for b. Write an equation where you have a value for m and b. You can then figure out another x and y that will work in that equation. 
Math
I have to see the line shown. We need the slope of the line shown. Grant's line will have a slope that is a negative reciprocal of the line shown. for example if the line has a slope of 3, Grant's perpendicular line will be 1/3. To find the other point, use the slope ... 
statstics
z = (x  32)/1.2 For 1: you have to use a ztable to find the value where 99% of the values are less than that number meaning that there is 1% in the upper tail. Ztables to differ from book to book, be sure to read it carefully. Once you have that z value, substitute it into... 
Inequalities
4x >8 excuse my typo x < 2 Lets pretend this is an equation for one minute (x3)/(x+1) = 5 Put in the 2 (23/(21) =5 5/1 =5 We are correct there... so.. Since we have an inequality, we have two choices for the final answer. x> 2 or x > 2 If we choose ... 
Inequalities
Multiply both sides times x + 1 x3 > 5x + 5 4x > 2 x<2 You are correct You choose 5 to check which is correct. (5 3)/(5 + 1) > 5 8/4 >5 2 > 5 That is correct 2 is greater than 5. 
Domain Interval Notation
You are welcome! 
Domain Interval Notation
Under the overall square root you have 3  square root of 25x^2 What is under the radical sign has to be positive. Domain is the X values that will result in a solution and not undefined. It looks like you can have x=5 and x =5 because that will give a square root of 0 to ... 
math
Your goal is to go from 3 equations in 3 variables down to 2 equations in 2 variables. It is up to you to decide which variable you want to eliminate. I think I might try eliminating the y. Add the first two equations together. since the y's are equal and opposite they ... 
math
I hope your other one didn't need matrices because..I did it the other way. 4 1 3 8 2 2 1 3 6 1 3 2 You want to manipulate the rows so that in the end, you end up with 1 0 0 a where a = the value for x 0 1 0 b where b = the value for y 0 0 1 c where c = the value for z. 
Stats help
There is data for these 5 people before and after the class. You have two sets of data and since it is the same people in both groups this is a dependent test. 
math
You have to look for a pattern. I would put them in order input 8 ___ 16 22 30 50 output___ 10 11 14 18 28 
science
D is not right. Electrons move all the time around the nucleus. The travels are not in the nucleus, but they travel around. There are different theories one is that they are in orbitals like the planets around the earth. Really there is cloud of electrons moving around the ... 
Math: Please check
48 is 16 x 3 Take the square root of 16 =4 4 square root of 3 Now look at n^9 that can be written as n times n^8 n^4 comes out and leaves n under the square root sign. your answer should be 4n^4 square root of (3n) One way to get an better understanding of this concept is to ... 
Math
36/390 Probability can be represented as a reduced fraction or as a decimal 
Math: Please help
To find the square root of 140 I started with 14 times 10 then 7 times 2 times 2 times 5 I have a perfect square of 4 and take the square root which puts the 2 out in front of the square root. 2 times the square root of (35) 
Geometry
Can you prove it by side angle side? AB = BC BD = BD it is a shared side Angle ABD = Angle CBD We have 2 sides and the angle between those 2 sides. I drew a picture. 
algebra
1/2  3m/4 + 7 = 4m 9  m/28 Let's get all of the m's on one side and all of the constants on the other. 1/2 + 7 + 9 =4m  m/28 + 3m/4 1/2 + 14/2+18/2 = 28(4m)/28  m/28 +21m/28 33/2 = combine the m terms and then solve for m by cross multiplying. 
Math
Sorry.. I didn't mean to post that. the answer gives us x =1 not 3 and we get to 6 dimes, but your problem is talking about more than 10 dimes. The one pile works because you have 4(1)+ 2 = 5(1) + 1 6 =6 . Now, we have to find a multiple that will work... Do you need more ... 
Math
You have to work with piles = x 4x + 2 = 5x +1 x = 3 if you substitute you have 14 dimes 3 piles of 4 = 12 plus 2 = 14 3 piles of 
Math
4 + 6+ 8 parts or slices 18 slice/5 people Each person can have 3 slices with 3 slices left over If you want to share the extra 3 slices with 5 people then each person gets another 3/5 of a slice. 
Math
You are right.. it could also be 36 
Math
You are looking for numbers between 30 and 50 These numbers must be in the 40s. Which number in the 40s has a 6? Would it be 46? 
Math
The equation is balanced. 1 liter of N2/ 3 liters of H2 5 liters of N2/ x liters of H2 Set the two fraction equal and cross multiply to solve for x. 
chemistry
There is a carbon in the middle. There is an H on each side of the Carbon plus one above with a Cl on the under the C.. The order doesn't really matter. You just have to show a Carbon with 3 H bonds and 1 Cl bond. Cl H C H H 
math
You distribute the power to each part. 14^4y^4 Most teachers would let you leave the answer like this. They wouldn't want you to work out 14^4. Maybe your teacher does. If so.. 14*14*14*14 
math
I don't see your exponent. Is it (14y)^4 ? 
math
You can either change all of the fractions to decimals or you can get common denomiators. You wil work with smaller numbers if you change 4/6 to 2/3 4/8 to 1/2 Now, you need a common denominator for 2/3 1/2 3/4 5/8 24 would work as your denominator. Once you have the fractions... 
math
71/568 were unsatisfied reduce the fraction to 1/8 
Science
Pressure is he best answer. 
math
How about.. If it is 40% off, then you are paying 60% of the price. .60 (60) = $36.00 
to Dr Jane
I just found it... I need to stay away from Language Arts... Thanks again. 
to Dr Jane
I just saw a posting by Brandi about tacos. Is that the one? My answer is still there and I think it is right. I do appreciate that you removed anything that I did wrong. I certainly don't want to give anyone the wrong answer. 
to Dr Jane
Thanks!!!!! 
to Dr Jane
Where did I make the mistake? I am trying to be careful. Sorry!!! Actually, I just found a mistake that someone else made. They posted a 46 for an answer of addition/subtraction of a polynomial. I can see how annoying this can be. I will be more careful. Thanks for letting me ... 
math
You could setup fractions and cross multiply: 1 = 1x so x = 1 
Math
You can use a Venn Diagram 12  5(0verlap) = 7 football 17  5 = 12 Add up 7 + 12 + 5 = subtract from 30 
physics
Force = mass times acceleration. 
Math
Unit rates is that you have to express the answer as 1 hour or per hour. 20 mi/ 2 h divide both by 2 and you will get some number of miles/1 hour 
math
$1000 + .09(2000) 
math
1 inch is about 2.5 cm so 7 inches would = ? 
math
percentage increase (1072  841)/841 You will get a decimal. Move the decimal point two places to the right and include the % sign. 
Math
more than is > 840/4 = 210 t>210 
fraction
5 3/4  3 2/5 Change 3/4 to 15/20 change 2/5 to 8/20 5  3 = 2 15/20 8/20 = 7/20 Ans. 2 7/20 
math
Six hundred thirty. There should not be an "and" unless there is a decimal point. Hopefully, it is 630 1000 mg = 1 gram So, you have less then a gram 1 gram/1000 mg = ?/ 630 
Math
2x^4 + 2x 1 add 2x^4 + 2x1 because these are two legs of the triangle. 4x^4 + 4x 2 Now subtract this from the perimeter to get the length of the base. Actually with signed numbers, we don't subtract, we add the opposite. 5x^42x^3 + x  3 + 4x^4 4x +2 x^4 2x^3 3x 1... 
maqth
I am thinking: 654 times 4. Multiply the 1 digit number times the ones digit in the number. Write down the ones value and carry the tens. For my example: when multiplying by 4 my first step is 6 carry 1 tens to the tens place multiply the 4 times the tens place and add in the ... 
math
Area = length x width Length = width + 6 A = lw l = w + 6 315 = (w+6)(w) 315 = w^2 +6w 0 = w^2 + 6w  315 0 = (w+21)(w15) w+21 = 0 w  15 = 0 w = 21 w = 15 discard the 21 because we don't measure distance in negative numbers. w = 15 l = 21 Multiply to be sure they equal... 
stats
It depends on your book It can be set up as Ho: mu1 = mu 2 Ha: mu1 does not equal mu2 or other books write it as: Ho: mu1  mu2 = 0 Ha: mu1  mu2 does not = 0 
stats
You can see that you have two samples here so you will do either an indep or dep. test. We usually use a dependent test if we are using twins or triples, married couples or if we repeat the test with the same students and using a different criteria. That did not happen here. 
physics
I am back... if the elevator is free falling, you would have zero gravity. I guess you should be worried. 
physics
Not if the elevator is moving. 
stats
You have to compare the 2.29 either with the significance level of say .05 You will go to a ttable look up the 2.29 with the correct degrees of freedom and compare that value with the .05. If it is less then you reject, if it is more you fail to reject. Another way would be... 
stats
Ho: Mu = 150 Ha: Mu >150 some books set up Ho: as Mu is less than or equal to because the go in the opposite direction of the Ha. The Ho always includes the = You are testing to see if your mean is significantly different from the known 150. When you do the test you will ... 
stats
This is a one sample test. It is one sample because you aren't comparing groups, etc. 
algebra 1
you have to think of two numbers that multiply to equal 48 and add to be 48 I can't think of anything that will work here. 48 = 24 times 2 or 2 times 24 = 48 times 1 or 1 times 48 Do you have a typo? 
Science
You are welcome. 
Science
You are correct. distance/ time = speed. Velocity is speed plus direction. 
College Mathematics
There are 13 clubs and then 3 jacks. 16/52 Using the rule P(J) = 4/52 P(C) = 13/52 P(C + J) = 1/52 the Jack of Clubs 
venn diagram
You have to subtract the overlap of 210 from 630 and that will just be P and won't include any Q. 
algebra
You can change 1/4 = a number /100 then you can compare the two fractions. multiply the numerator and the denominator of 1/4 by 25 to get ?/100 
algebra
(5x 3)(5x3) 25^x^2 30x +9 I start with the above factors because of the 25 and the 9 and the requirement of one distinct room. So.. a15 = 30 
STAT
1. 6 feet = 72 inches You need to find the z score (number  mean) divided by SD 72 66/2.5 = z score Then use a standard ztable to find the area of under the curve to the right of that number. This number will be your %. 2. Find the zscore for 67 and 65. Find the area ... 
maths
for a numerical value, use a calculator to find the square root of 2. Multiply that answer by 2 and add 3 Then take the square root of that final answer. 
Chem
nonpolar is when they share electrons equally. 
Math: Probability
dependent in the first one would be choosing a cookie at random and eating it and then choosing another. By eating that first cookie, you changed the probability of getting a second cookie. Indep for the second one would be flipping a coin and rolling a cube. 
Algebra
Yes, because that will give you a value of 0 height in 3 s.