GRE quant Flashcards
How do you find Q1, Q2, Q3, Q4
first find Q2 (median), then Q1 is the median of the lower half, Q3 is the median of the higher half, and Q4 is the max
Definition of a percentile
% of the data that is below the amount in question, or % of the data that is at or below the amount in question
What is the range?
The range is the difference between the greatest number in a list and the smallest number in a list. For example the range for 11, 10, 5, 13, 21 is 21-5= 16
How do you calculate the interquartile range?
Q3-Q1
How do you find the standard deviation among 0,7,8,10, 10
1) find the average/mean, which equals 7
2) (7-0)^2 + (7-7) ^2 + (7-8) ^2 + (7-10) ^2 + (7-10) ^2 = 68
3) 68/5=
4) Take the square root of 13.6, which is 3.7
Area of a circle
A= πr^2
Circumference of a circle
C = 2πr
Area of a triangle
A = 1/2b*h
Area of a rectangle
A = bh
The mean of a sample is 32.5 and the std deviation is 7. What is 2 standard deviations away? How many standard deviations above or below 32.5 is 48?
Q1) 46.7
Q2) approximately 2.2
2 * 3 * 10 = 60. 2, 3, 10 are ______ of 60
factors
25 is a _______ of 5, 1, 25.
multiple
1 is a factor of every integer. Is this true or false?
True
What is the least common multiple of 40 and 80?
160
What is an integer that only has 2 divisor, the number 1 and itself?
A prime number
What is -3 ^2
-9
What is (-3) ^2
9
a ^0
1
a ^-3
1/a^3
What percent of 150 is 12.9?
8.6%
15 is 60% of what number?
25
An investment in a mutual fund increased by 12% in a single day. The original value was $1,300. What is the new value?
$1456
The monthly enrollment at the preschool decreased by 8% one month, and then increased by 6% the next month. What is the cumulative % change?
2.48% decrease
(x^a)(x^b)
x^a+b
(3^2)(3^3)
3^5
5^5/5^4
5^5-4 = 5^1
t^3/t^8
t^3-8 = t^-5 = 1/t^5
(2^2)(4^2)
8^2
(10z)^3
10^3 * z^3 = 1,000z^3
(3/4)^2
9/16
(x^a)^b
x^a*b
(3^3)^2
3^6
How do you solve for x in: ax^2 + bx + c
x = -b+- √b^2 - 4ac/ 2a
find x for 2x^2 - x - 6
x = 2, and x= -3/2
What is the formula for the slope of a line?
y2-y1/x2-x1
Two lines are _____ when their slopes are the same, and two lines are _____ when one line’s slope is the negative reciprocal of the other
parallel, perpendicular
Solve for the x-intercept: y= 0.75x -1.5
x= 2
How do you solve for the y -intercept?
Make x = 0
Find the vertex of: y= 5x^2 - 2x +15
(2, -5)
What is the formula for the x-vertex
-b/ 2a
What points does x + y = 3 and 3x - 2y = 4 intersect at?
x = 2, y = 1
What is the sum of the measures of the interior angles of a hexagon?
(6-2)(180) = 720
If triangle ABC has two angles that equal 50, what does that third angle equal?
80
Equation to find the length of the hypotenuse
√a^2 + b^2
For all parallelograms the Area is?
A = bh
What is the area of a trapezoid?
1/2 (b1 + b2) (h)
Find the length of arc ABC of a circle with radius 5, the degree measure is 50.
4.4
Find the sector of the circle region bound by ABC, angle 50 and radius of 5.
10.9
What is the formula for the volume of a rectangular solid
V = lwh
What is the formula for the surface area of a rectangular solid
A= 2(lw+lh+wh)
What is the formula to find the volume of a cylindrical solid
V=πr^2h
What is the formula for the area of a cylindrical solid?
A= 2πr^2 + 2πrh
