Math questions :D ! PLease help (:

Test Preparation SAT Preparation
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<p>These questions are from PR 11 practice tests</p>

<p>8) When the organizers of a bake sale sell brownies for $1.50 each, they sell 7 brownies every hour. Then the brownies are sold $2.00 each, 5 brownies are sold each hour. If "X" is the price per brownies in dollars, and "f" is the number of brownies sold per hour, then which of the following could represent "f" as a function of ''X''?</p>

<p>a. f(x)= 4x + 1
b. f(x)= 6x - 7
c. f(x)= -3x + 11
d. f(x)= -4x+ 13
e. f(x)= -6x+16</p>

<p>ANSWER: B</p>

<p>13) In a list of four even numbers, the mean, median, and mode are all equal. Which of the following CANNOT be done to the list if the mean, median, and mode are to remain equal?</p>

<p>a. Add one number to the list
b. Add one number to the list that is greater than the mean
c. Add two distinct numbers to the list
d. Add two numbers in the list.
e. Remove the first and last number of the list</p>

<p>ANSWER: B</p>

<p>And last is # 16. I don't know how I'm going to type it since it's graphs. So if anyone has the PR 11 practice test 2011 edition. Please go to pg 412 and look at number 16. </p>

<p>Please explain (:</p>

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<p>this is one of the times where i look at the title of the thread, think i can help…but then get raped by the questions…im keen on DrSteve or Xiggi or Silverturtle replying so that i can figure out how the hell do these monstrous PR problems.</p>

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<p>The first one is worded poorly, but it is a function problem. The function gives you the rate of sales as a function of the price. You are looking for the answer choice that gives you an output of 7 (the rate) when you use x=1.5 (the price) and also gives you an output of 5 (the rate) when you use x = 2 as the price.</p>

<p>When you check the answers, you will see that D (not B) is the one that works.</p>

<p>For the next one, try lists that rule out possible answers…</p>

<p>For A, from 2,2,2 to 2,2,2,2 works</p>

<p>For C, from 2,2,2 to 0,2,2,2,4 works</p>

<p>For D, from 2,2,2 to 2,2,2,2,2 also works (as does the numbers from C)</p>

<p>For E, from 0,2,2,2,4 to 2,2,2 works.</p>

<p>No way to make B happen…</p>

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<p>Smae here. I thought it’s going to be a breeze and get like 800. But after I saw that section I was like NOOOOO! XD</p>

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<p>The first question is very poorly worded and doesn’t even really make sense as written. But it’s not too hard to see what was intended. Let me try to clean up the question a bit so that it makes some sort of sense:</p>

<p>When the organizers of a bake sale sell brownies for $1.50 each, they sell 7 brownies every hour. When the brownies are sold for $2.00 each, 5 brownies are sold each hour. If f(x) is the number of brownies that the organizers sell per hour at a price of x dollars, then which of the following could represent f as a function of x?</p>

<p>a. f(x)= 4x + 1
b. f(x)= 6x - 7
c. f(x)= -3x + 11
d. f(x)= -4x+ 13
e. f(x)= -6x+16</p>

<p>Even with my rewording I still think it’s a poor question. But at least now it can be done. In any case, I like pc’s solution. The strategy to use here is to simply “plug in the given points.” The trickiest part is just identifying the points. Note that a point has the form (x,y) where x is a price, and y is a quantity.</p>

<p>This is a “supply and demand”-type question, a standard application of (linear) functions. These are particularly tricky since the input is a price, and the output a quantity. </p>

<p>A slightly easier application would be of cost functions where the input is a quantity, and the output a price (the cost for x items).</p>

<p>I haven’t seen this type of “supply and demand” question on an actual SAT (I’m not saying it hasn’t appeared - just that I haven’t seen it).</p>

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<p>ahh your wording makes it better DrSteve. </p>

<p>Thus the answer is D.</p>

<p>Of course you can do a very long algebraic way or just easily plug in x = 1.50 or x = 2.00 to find out if each answer gives you its respective hour. Takes about 25-45 seconds at most with mental math :)</p>