Friday, October 1st, 2010

### Solution:

- 1L = 1.057 fl qt
- 1L = 1000 ml
- 1.079 fl qt = 1.079 x 1.057 L = 1.140503 L
- 1.140503 L = 1140.503 ml

Friday, October 1st, 2010

### Solution:

Base ten blocks are a mathematical manipulative used to learn basic mathematical concepts including addition, subtraction, number sense, place value and counting. You can manipulate the blocks in different ways to express numbers and patterns. Generally, the 3-dimensional blocks are made of a solid material such as plastic or wood and come in four sizes to indicate their individual place value: Units (one’s place), Longs (ten’s place), Flats (hundred’s place) and Big Blocks (thousand’s place). There are also computer programs available that simulate base ten blocks.

Since the number that is being modeled has a zero in the tens place and a zero in the ones place, there are no Longs or Units. Since the number is less than 999, there are no Big Blocks. That leaves only Flats, and there must be five Flats. Since each Flat represents one hundred, the number must be 500.

Friday, October 1st, 2010

### Solution:

- A quantitative variable is a phenomenon measured in amounts, that is, numerical units. For example, a numerical score is a quantitative variable.
- The measurement is based on a scale of 1 to 4.

Tuesday, September 7th, 2010

### Solution:

Tuesday, September 7th, 2010

### Solution:

MUx(x,y) = Derivative of U(x,y), treating y constant.

MUx(64,25) =

MUx(49,36) =

Tuesday, September 7th, 2010

### Solution:

- First, factorize the numerator using prime numbers: 288 = 2*12*12 = 2*3*4*3*4=2*2*2*2*2*3*
- Second, factorize the denominator: 1155 = 5*231=5*7*33 = 5*7*3*11
- Notice that the numerator and denominator have only one factor in common (3).
- Restate the ratio after removing the common factor
- New numerator = 2*2*2*2*2*3 = 96
- New denominator = 5*7*11 = 385
- Same ratio in lowest terms:

Tuesday, September 7th, 2010

### Solution:

A scientific experiment has three types of variables: independent, dependent and controlled. Please click on this link to get details: http://www.sciencebuddies.org/mentoring/project_variables.shtml.

Tuesday, September 7th, 2010

### Solution:

We can factor the expression as follows:

To figure this out, we used the quadratic formula (see http://en.wikipedia.org/wiki/Quadratic_equation):

w =

We recognized that y= is a quadratic equation in the form of y= where a=2, b=-5 and c=-10.

To confirm that our calculation are right, we decided to plot the graph of y = by plugging in various values of w.

As you can see, there is a root at approximately -1.3 and another root at approximately +3.8. So we know approximately what the values of a and b are. We could use a calculator to get closer and closer to the exact values of a and b. For example, if we try w=3.8, we get a value of y = -0.12. If we try a slightly different value, we can see if we’re getting closer to zero or farther away: w=3.81 produces a value of y=-0.018, so we know that 3.81 is a better approximation than 3.8. If we keep calculating closer approximations of the root, we will arrive at the value of b that we calculated using the quadratic formula:

Monday, September 6th, 2010

### Solution:

First, let’s make sure we understand what we mean by “mathematical induction”: “Mathematical induction is a method of mathematical proof typically used to establish that a given statement is true of all natural numbers. It is done by proving that the first statement in the infinite sequence of statements is true, and then proving that if any one statement in the infinite sequence of statements is true, then so is the next one.” (Wikipedia) We have pasted below another more detailed explanation of how to create a proof using mathematical induction (see “Appendix” below).

Let’s now take the equation you provided: 1*3+2*4+3*5+…+n(n+2)=

We can show that this is true for n=1: 1*3 = = = 3

Now let us assume that the statement is true for n = k. If it is, then we will prove that it has to be true for n=k+1:

WTS è = +

* *

= +

=

=

=

=

= **QED**

In the above proof, WTS means “want to show” and QED means “quod erat demonstratum” (“which was to be demonstrated”).

## Appendix

Here’s another more detailed explanation of how to create a proof using mathematical induction:

Monday, September 6th, 2010

### Solution:

- A = number of ounces of the first alloy
- B = number of ounces of the second all
- A+B=32
- 0.16 A +0.28 B = 32 x 0.25
- Since A + B = 32, we know that A = 32 – B. You can then re-write the equation above as 0.16 (32-B) + 0.28 B = 32 x 0.25
- This can be simplified to 5.12- 0.16 B + 0.28 B =8
- Or, 0.12 B = 2.88
- Or B = 24
- So A = 8