Post your hardest SAT I questions

<ol>
<li>The first 5 terms will be a, 3a, 9a, 27a, 81a
The sum will be a + 3a + 9a + 27a + 81a = 605
121a = 605 -> a = 5</li>
</ol>

<p>"tx + 12y = -3</p>

<p>The equation above is the equation of a line in the xy-plane, and t is a constant.
If the slope of the line is -10, what is the value of t ?"</p>

<p>Here is another way. Using the the equation form ax+by+c=0
slope will be -a/b and y-intercept will be -c/b. I memorized these.
Back to the question. the slope will be -t/12=-10 which you can easily solve for t=120.</p>

<p>This is a pretty productive thread.</p>

<p>Bump.</p>

<p>try each answer starting w c, better if you have an 89</p>

<p>I beleive its d/8c
and 14. Plug in numbers</p>

<p>that is incorrect. the right answer is A</p>

<p>the answer of the cylinder problem has to be A!</p>

<p>Please, I need the solution to this problem : </p>

<pre><code> Machine A and Machine B are used to manufacture 660 sprockets. It takes machine A ten hours longer to produce 660 sprockets than machine B. Machine B produces 10% more sprockets per hour than machine A. How many sprockets per hour does machine A produce?

                                                                Thanks.

</code></pre>

<p>Could someone please help me out with this problem? </p>

<pre><code> Mary is twice as old as anna was when mary was half as old as anna will be when anna is 3 times as old as mary was when mary was 3 times as old as anna. The combined age of mary and anna is 44. how old are mary and anna ?

                                                                                 Thanks.

</code></pre>

<p>Let the number of hours taken by B to produce 660 sprockets be x. Then A will take (x+10) hours.
Also y be the number of sprockets A produces in 1 hr. Then B will produce 1.1y in 1 hr. </p>

<p>y(x+10)=x(1.1y)
xy+10y=1.1xy
10y=0.1xy
x=10/0.1=100 </p>

<p>A will produce 660 sprockets in x+10 hours==>660 in 110 hrs.
Therefore in 1 hr A produces 660/110=6 sprockets.</p>

<p>Help me out with this please.
An initial deposit of $2,000 is placed in an account that pays 5.5 percent annual interest, compounded quarterly. If no other deposit or withdrawals are made, after how many quarterly interest payments does the amount in the account first exceed $4,000 ?</p>

<p>A) 51
B) 52
C) 53
D) 50</p>

<p>Another difficult Math question…</p>

<p>A polygon is inscribed in a circle. If some diameter of the circle divides the polygon into two regions of equal area, which of the following must be true ?</p>

<p>I) The polygon is regular
II) The center of the circle is inside the polygon
III) The polygon is symmetrical about some diameter</p>

<p>A) None
B) I only
C) II only
D) III only
E) II and III only</p>

<p>jaja, i cant believe that this problem trouble me more than a hour, if you use all in 10$ you have just 1 posibilite, if you use all in 10 exept one, you gonna have 2 possibibilites (2 and 5 dollars). if its two, will be 2+1 because, you have one possibilite 2 of 2 dollars, other in 1 of 2 dollars and other in 2 dollars, and because the rest have to be in 5 dollars, it dont cares and it passes trough all the possibilites, so it allways will be 1+2+3+4…+202, so if you have the formula of the consecutive numbers, n(n+1)/2 you will have 2</p>

<p>20503
so its b</p>

<p>A=production in A machine
B=production in B machine</p>

<p>Tha machine B works 10% faster than A, thats the same that B, its 110/100 faster than A or 1.1 times, when the machine B ends, the machine A still have 0.1 of the 1.1 to process, so if its is 10 hours to end, then 1.1 is 110 hours and then B is 100 hours so the machine A works to 6 elements/hour</p>

<p>2x - 5y = 8
4x + ky = 17</p>

<p>For which of the following values of k will the system of equations above have no solution?</p>

<p>(A) -10
(B) -5
(C) 0
(D) 5
(E) 10</p>

<p>Is it (A)?
I do not know the answer; I tried to find it on CB’s website, but my search turned out to be useless. (This is from last year’s PSAT Score Report.)</p>

<p>guess this would be very hard if you were in high school. it’s actually a basic linear algebra problem, however.</p>

<p>Subtract the two equations to get that 2x + (k+5)y = 9
if k = -5, then 2x = 9, an impossible solution
the answer, then, is (B)</p>

<p>I bet the question mentioned that the solution would have to be of integer value…</p>

<p>For the question:
2x - 5y = 8
4x + ky = 17
For which of the following values of k will the system of equations above have no solution?</p>

<p>The answer is (A), -10.</p>

<p>To see why this is the answer, first think about the fact that the points (x, y) that satisfy a linear equation lie on a straight line. If you have two linear equations in just two variables x and y, and therefore you have two straight lines in a plane, there are only three options:

  1. The lines intersect in a single point. In this case there is a solution of the system of equations. It is the point of intersection.
  2. The lines actually lie on top of each other. In this case, there are an infinite number of solutions of the system of equations (all of the points on the line).
  3. The lines are parallel to each other (and they are displaced from each other). In this case, there will be no solution of the system of equations, because the lines do not intersect.</p>

<p>So, what will make the lines parallel? They will be parallel if they have the same slope. Since the coefficient of x in the second equation is 4, that is twice the coefficient of x in the first equation (2). Therefore, if you take twice the coefficient of y in the first equation (-5), you get -10 for k. At this point, we know that the two lines have the same slope. Are we dealing with case 2 (infinite number of solutions) or case 3 (no solutions)?</p>

<p>If we multiply the first equation by 2, we get 4x - 10y = 16, while the second equation with k = -10 is 4x - 10y = 17. The two lines are parallel, the equations are incompatible, and there is no solution of the system of equations. Therefore the answer is (A), k = -10.</p>

<p>In three dimensions, there is an additional option that the lines might be “skew.” Skew lines are not parallel, but they also do not intersect. Skew lines are located in parallel planes (that are separated from each other). If skew lines were projected into a single plane, they would intersect.</p>

<p>Perched atop a sandstone mesa, Acoma Pueblo is the oldest inhabited comminity in North [America, currently a population of] about fifteen families.</p>

<p>answer:</p>

<p>America and currently has a population of </p>

<p>why i didnt choose this answer is because there is no comma before and.
can someone explain this answer please?</p>

<p>A pioneer in the nursing field, [Florence Nightingale’s insistence on sanitary conditions in hospitals] increased patients’ survival rates considerably. </p>

<p>i thought it was correct and chose A.
but the answer is:
Florence Nightingale insisted on sanitary conditions in hospitals and thereby (once again - why there is no comma before and?)</p>

<p>There are a few conjunctions that do not require commas, in the opinion of CB. These are and, or, and but. (Well, they don’t require commas when they are just linking two things.)</p>

<p>The reason that "A pioneer in the nursing field, Florence Nightingale’s insistence . . . " is not correct is that CB is quite strict about the rules for modifiers (in defiance of logic, to some extent). They feel that this construction means that it’s “Florence Nightingale’s insistence” that is the pioneer in nursing, rather than Florence Nightingale herself.</p>

<p>

</p>

<p>The actual grammatical rule is that unless there are two subjects, no comma is needed. For example: </p>

<p>My town is the largest in our state and has a population of 10,000 people. </p>

<p>This statement would not need a comma as there is only one subject–my town. </p>

<p>An example where the comma would be needed is:</p>

<p>My town is the largest in the state, and it has a population of 10,000 people. </p>

<p>This would need a comma because there are two subjects-- “my town” and “it.” </p>

<p>That is why the statements you previously mentioned do not need the comma. They both have only one subject-- “the community” and “Florence Nightingale.”</p>