Thursday
May 5, 2016

# Posts by Marth

Total # Posts: 764

math
It depends on the distribution of x bar.
February 20, 2016

math
6 topping choices, 2 toppings per pizza: 6 choose 2, which is 6!/(2!4!)
February 20, 2016

Stats/Probability
"Red OR Yellow" should be a giveaway. Here P(A and B)=0 because a red car is not yellow. P(A)+P(B)=0.12+0.04 = 0.16
February 20, 2016

computer science
4×512MB = 2GB = 2^31 bytes. To address any byte requires 31 bits.
February 20, 2016

theoretical probability
There are 2 digits (8,9) greater than 7. So every student has a 1/5 chance of choosing a digit greater than 7. With 25 students, the expected number that choose a digit greater than 7 is 25/5 = 5. I would not say the "predicted" number, but rather the "expected&...
February 20, 2016

math
b) He can throw 5 types of pitches each pitch. With 5 pitches, there are 5^5 possible combinations.
May 20, 2011

algebra
When the world record is less than 3.1, R is less than 3.1. 3.1 = -0.075t + 3.85 Solve for t (in years after 1930).
May 20, 2011

computer science
File sizes are given in bytes, while download speeds are given in bits. 4 GB = 4*1024 MB = 4*1024^2 KB = 4*1024^3 Bytes - 4*1024^3*8 bits. 43.2kbps = 43.2*1000 bits per second. The time required is 795.364s, or 220.935 hours. Note that 43.2kbps is quite a low bandwidth.
May 20, 2011

Math
The fence forms the perimeter of the rectangle. What is the perimeter?
May 19, 2011

geometry
It doesn't. 100 is not divisible by 6, nor is 83 divisible by 5.
May 14, 2011

Math
13 is a good guess. But when in 2011 do they actually turn 13?
May 14, 2011

math
What is the equation for the volume of a sphere? Try googling it.
May 14, 2011

math
How many inches are in a foot?
May 14, 2011

What is the length of <-1,-2>? Divide <-1,-2> by its length, giving the result a length of 1 - an unit vector.
May 14, 2011

math
How could you get only x on the left hand side?
May 14, 2011

math
Is the domain of g equal to A? Is the range of g a subset of B? if both are true, then g maps A to B.
May 14, 2011

math geometry
Use Pythagorean Theorem. a^2 + b^2 = c^2, where c is the hypotenuse of the right triangle.
February 14, 2011

Math
Find the slope and y intercept of each, and compare. m = (y1-y2)/(x1-x2) to find the slope. y - y1 = m(x-x1) to write the line in slope-intercept form.
February 9, 2011

Algebra
You can factor out a 4a from each term.
February 3, 2011

Math Algebra 2
Substitute in the values of p and r. p = 10 r = -4 p^2 - r^2 = (10)^2 - (-4)^2 = ?
January 27, 2011

MATH
No two numbers add to 50. Therefore we must use at least 3 numbers to get the sum. 25+19+6 = 50: a solution exists for 3 numbers.
January 27, 2011

math
(1/8)-(1/8)2+(1/8)3 = (1/8)(1-2+3) by factoring.
January 25, 2011

beginning algebra
2 + 7/y = 3/5 7/y = 3/5 - 2 y/7 = 1/(3/5 - 2)
January 22, 2011

algebra
The probability that Jonas gets an orange is 5/11. Given that Jonas gets an orange, the probability that Beth gets an apple is 4/10. So the probability that Jonas gets an orange and Beth gets an apple is (5/11)*(4/10).
January 20, 2011

algebra
y - y1 = m(x - x1) The point (x1, y1) is given as (4, -5). The slope m is given as -3.
January 20, 2011

MATH
881/5 = 880/5 + 1/5
January 18, 2011

Geometry
Let x and y be the sides. By Pythagorean Theorem, x^2 + y^2 = 600^2. x+y+600 = 1400
January 18, 2011

Math
Elaine takes 2.8s more than Pamela: Elaine takes 2.8s + 52.3s =
January 18, 2011

Math
To find the inverse, swap f(x) and x: f(x) = 10x-5 x = 10f^-1(x)-5 Now solve for f^-1(x).
January 18, 2011

Math
Set up a proportion: 8%/56 = 100%/x
January 15, 2011

Algebra
x^2-6x-3=0 x = (-b +/- sqrt(b^2-4ac))/(2a) x = (6 +/- sqrt(6^2 - 4(1)(-3)) ) / (2(1))
January 15, 2011

algebra
Plug the values in. h = 50m t = 2s v = 30m/s h+vt+4.9*t^2=?
January 15, 2011

math
The difference of two squares is a^2-b^2, for a and b any expression. It should be easy to determine if a polynomial fits that form.
January 15, 2011

physics
V=d/t d=V*t Let t be the time the man is jogging. t-2 is the time the dog is running (since the dog waits 2s). When they catch up with each other displacement will be equal. (4m/s)(t-2)=(1.8m/s)(t)
January 15, 2011

Preap Physics!!
There are several types of potential energy - spring potential energy, chemical potential energy, etc.
January 11, 2011

math
If the relationship is linear, then the line formed by any two points will pass through all points. Find the line through the first two points. Then check to see if the rest of the points are on that line.
January 11, 2011

algebra
There are two solutions because of the absolute value sign. x-3x+5 = 7 or x-3x+5 = -7
January 11, 2011

algebra 2
You can factor out 4x from both terms.
January 10, 2011

algebra
Jeffs car takes 20% less gas, so it gets 21/(1-0.2) miles per gallon. To drive 570 miles at 21 miles per gallon requires 570/21 gallons.
January 10, 2011

math
Teaching makes you learn something well. You've had scientific notation in class, right? Pretend I don't know scientific notation, and explain to me what it is. (That will be your answer).
January 10, 2011

Algebra
Let x be the amount of time of the breakeven point. Then 84+50x = 60x.
January 9, 2011

Algebra 2
Use synthetic division with -3, then factor the remainder.
January 9, 2011

algebra
f(x) = 2x^2-3x f(0) = 2(0)^2-3(0) = 0 f(-1) = 2(-1)^2-3(-1) f(2)=?
January 9, 2011

math
Let a be the value of "a", e be the value of "e", etc. for i, o, and u. Audacious has a u a i o u = 260. So 2a+i+o+2u = 260. Do the same for the other 4 words; you have 5 equations for 5 variables.
January 9, 2011

algebra 2
The zeroes are 1, 2, and 3, so the factors are (x-1), (x-2), and (x-3). Those are 3 factors for a 3rd degree polynomial, so no other factors are needed. f(x) = C*(x-1)(x-2)(x-3), where C is any constant. f(0) = 18 allows you to determine C.
January 9, 2011

probability
There are 15 choose 4 ways to choose 4 toppings. There are 15 choose 2 ways to choose salami, green pepper, and 2 other toppings. P{salami and green pepper) = C(15, 2) / C(15,4).
January 9, 2011

Math: Algebra 2
Try factoring out (2x-3) through grouping.
January 9, 2011

Math
Suppose you buy x shirts to be shipped as one order. What is the cost of the shirts? What is the cost of shipping?
January 9, 2011

geometry
The diagonal forms a right triangle with 2 sides of the square. The sides are of equal length, so you can use Pythagorean Theorem to find a side of the square.
January 9, 2011

Algebra
What variables did you use in part a?
January 9, 2011

Algebra II
x^2+2x-3 factors into (x+3)(x-1). You can divide x^4-5x^3-16x^2+23x-3 by (x+3) and (x-1) using synthetic division, which may be easier.
January 9, 2011

math analysis
If csc(x) = 30/150, sin(x) = 150/30. That is not in the range of sine.
January 9, 2011

Math
Try writing an equation for each problem. It's easy to make a mistake while glancing over the answer choices.
January 9, 2011

Calculus
The derivative of ln(u) is u'/u. Use Chain Rule for the rest.
January 9, 2011

math
The points at the tail of the skew affect the mean, but the median will remain in the middle of the curve.
January 9, 2011

algebra
-2x-<-2x-1 -< is not defined.
January 7, 2011

Math
Use L'hopital's Rule.
January 7, 2011

math
a > b = "a is greater than b" a < b = "a is less than b"
January 6, 2011

algebra
January 6, 2011

physics
q1 exerts a force on q in the positive direction, and q2 exerts a force on q in the negative direction. F = k(q1q2)/r^2 is the force exerted on one point charge by another. ΣF = k(q*q1)/(0.24)^2 - k(q*q2)/(0.37)^2 = 24. q and q1 are given. q2=?
January 6, 2011

Math
The player makes 60% of the shots. So the odds are 60:40 in favor of her making the first shot.
January 6, 2011

1) Yes, the gravitational force diminishes the farther you get, but by what factor? Check the equation. 2) The speed of the earth keeps it in orbit around the sun. Changing the mass changes the gravitational force, which is also the centripetal force for the orbit.
January 5, 2011

algebra
January 5, 2011

math
You gain \$3 if you get a 6, and always pay \$0.90. E[X] = (1/6)*3 - \$0.90
January 5, 2011

math
Pythagorean Theorem: a^2 + b^2 = c^2 c is the hypotenuse
January 5, 2011

algebra
25% was marked off the original price of \$88.
January 4, 2011

fraction x whole number
7/10*30 = 7/10*10*3 = 7*3 = 21
January 4, 2011

algebra
If |3n+5| = 7, then 3n+5 = 7 or 3n+5 = -7. There are two possibilities for n; find both.
January 4, 2011

Math
18 < 20-w 18-20 < 20-w-20 -2 < -w Flip the inequality sign when multiplying by -1. 2 > w
January 4, 2011

science
The boiling point and condensation point are identical.
January 4, 2011

Math pre-algebra
3/1.65 = 5/x
January 4, 2011

math
Let x be the amount of money Beth has. Let y be the amount of money Suzy has. "beth has \$0.60 more than suzy." x = 0.60+y. "together they have \$8.20." x+y = 8.20 Solve the system of equations.
January 4, 2011

Math
<-- -10 ... -7 -6 ... 0 1 2 ... --> Numbers are ascending left to right. Is -7 to the left or to the right of -6?
January 4, 2011

Math
Draw a number line, and label -7 and -6.
January 4, 2011

Math
x+8 < 11 x+8-8 < 11-8 x < 3 Inequalities are almost like regular equations.
January 4, 2011

Math
x+8<11 implies x<3. What is your question?
January 4, 2011

Pre-Algebra
12+5 > y-5+5 17 > y
January 4, 2011

math
Ok. Then the perimeter of the triangle is w + l/2 + 5. So w+l/2+5 = 12m, and 2(l+w)=22m.
January 4, 2011

math
Is the base of the triangle the width of the rectangle, and the height of the triangle half the length of the rectangle?
January 4, 2011

math
Are you referring to the triangle formed by the diagonal of the rectangle and two of its sides? If the dimensions are 8m by 3m, the hypotenuse of said triangle cannot be 5m.
January 4, 2011

math
The perimeter of the rectangle is 22m. So 2(l+w) = 22. l+w = 11 l = 11-w Also, l^2+w^2 = 5^2 by Pythagorean Theorem. Substitute in l = 11-w: (11-w)^2+w^2=5^2
January 4, 2011

math
Let l be the length, and w be the width, of the rectangle. The perimeter of the rectangle is 2(l+w). The perimeter of the triangle is l+w+sqrt(l^2+w^2). sqrt(l^2+w^2) is the hypotenuse of the triangle. There are two equations and two variables. Find l and w.
January 4, 2011

math
(2/5)Q <= -18 Q <= (-18)/(2/5)
January 4, 2011

Math
2+m < 2 2+m-2 < 2-2 m < 0
January 4, 2011

Math
I appreciate trying to help, but please work out the problems to show how the answer is reached. (It also helps to check your work). Standard form of a line is ax+by = c, with a, b, and c integers. y+2 = (1/2)(x-4) Distribute the (1/2). y+2 = x/2-2 Multiply by 2 to make the ...
January 4, 2011

Math
Factoring the tens is a technique for mental multiplication which relies on the fact that 10*n, for any real number n, is easy to compute. 6*2 = 12 is a memory value. 6*20 = 6*2*10 = 12*10 = 120 60*20 = 6*10*2*10 = 12*10*10 = 1200
January 4, 2011

algebra
Substitute in x = 35-5y in 4x+9y = 52. 4(35-5y)+9y = 52 Solve for y. Then, plug the value of y into either of the original equations to find x.
January 4, 2011

algebra
6.67*10^-11 = 6.67/10^11
January 4, 2011

Math
10-4(5x+1) Distribute the 4 =10-20x-4 =6-20x
January 4, 2011

Math
This is a simple triangle problem - it may help to draw it out. Draw the height perpendicular to the ground, and the ramp is the hypotenuse. The solution is a proportion. Let x be Pam's height. Then 15/9 = (15+20)/x. x=?
January 4, 2011

Math/Trig
The period of the parent function is 2pi. The factor of 1/2 applied to x changes the period to 2pi/(1/2) = 4pi.
January 4, 2011

Math
t is the price of the movie ticket. We know that 3 tickets is less than twenty dollars, because the student got change back. 3t < 20
January 3, 2011

math
That is an expression. What is your question?
January 3, 2011

math
8*5*9 = 4*2*5*9 = 4*10*9 = 36*10 = 360
January 3, 2011

algebra
Given the slope m and the point (x1, y1), use the equation y-y1 = m(x-x1) to find the equation of the line.
January 3, 2011

algebra
At any value of x on the horizontal line, y is still 2. Therefore, y=2 is the equation of the horizontal line. Similarly, x is always 3 on the vertical line. So x=3 is the vertical line.
January 3, 2011

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