HArf Math Quefstion!

Test Preparation SAT Preparation
1

<p>1)
x=.3y</p>

<p>The equation above gives the decimal equivalent of x, where y represents the hundredths digit. If x=P/t, where P is a 1 digit integer and t is a 2 digit integer, which of the following could be the hundredths digit of x?</p>

<p>A) 2
B) 3
C) 7
D) 8
E) 9</p>

<p>2)
y=4x-9
An equation of a line in the xy plane is given above. What is the x-coordinate of the point on the line for which the y-coordinate is 1 greater than the x coordinate?</p>

<p>3)
If |x|-|y|=10, which of the following statements is true about x-y</p>

<p>I) It could be equal to 0
II) It must be less than 100
III) It must be positive</p>

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

<p>Answers and Explanations would be great! Thanks!</p>

2

<p>As long as P and t are relatively prime (which the question should clarify), p=8, t=25, thus y=2 ----> [A]</p>

<ol>
<li><p>I am getting x=3.3333 (just graph it)</p></li>
<li><p>just make a table:</p></li>
</ol>

<p>x=10:y=0
x=20:y=+/-10
x=30:y=+/-20</p>

<p>Clearly I is false
Clearly II is false (x=100, y=-90 is a solution, yet x-y>100)
x=-30, y=20 is a solution so III is false</p>

<p>[A]</p>

3

<p>

</p>

<p>You have two unknown variables, thus you need two equations.</p>

<p>Primary Equation:
y = 4x-9</p>

<p>Secondary Equation:
y = x + 1</p>

<p>Substitution:
x + 1 = 4x - 9
x + 10 = 4x
10 = 3x
x = 10/3</p>

4

<p>i don’t even get the first question?</p>