GRE Studying
what is the formula for permutations of indistinguishable items?
(N!)/ ((r1!)(r2!)(rn!))
The number of ways to arrange a set of items in a circle is the following formula:
(k-1)!
median formula in odd # of terms:
(n+1)/2 position
(x^a)/(y^a)
(x/y)^a
Perfect Squares to Memorize
0, 1, 4, 9, 16, 25, 36, 49, 64, 81, 100, 121, 144, 169, 196, 225
Perfect Cubes to Memorize
0, 1, 8, 27, 64, 125, 216, 343, 512, 729, 1,000
2^0
1
In a probability space, the probabilities must sum to
1
The GCF of any two consecutive integers is _______
1
When a nonzero base is raised to the zero power, the expression equals
1
Square root of 2
1.4
Square root of 3
1.7
4^5
1024
How many edges does a cube have?
12
5^3
125
2^7
128
2^4
16
4^2
16
2^1
2
What are the prime numbers less than 100?
2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97
Square root of 5
2.2
4! = ?
24
3^5
243
5^2
25
2^8
256
4^4
256
3^3
27
2^n + 2^n
2^(n+1)
3^1
3
2^5
32
3^n + 3^n + 3^n
3^(n+1)
2^2
4
4^1
4
4^n + 4^n + 4^n + 4^n
4^(n+1)
5^1
5
2^9
512
5^4
625
2^6
64
4^3
64
2^3
8
3^4
81
3^2
9
What is the distance formula
Distance = Rate x Time
What is the 'percent less than' formula?
Final = (1-(percent/100)) x initial
when n is added / subtracted to every number in the dataset, what happens to the IQR
IQR2 = IQR1
What is the basic probability formula?
P = (favorable # of outcomes) / (Total # of outcomes)
If A and B are not independent, what is the formula for P(A and B)
P(A and B) = P(A) * P(B | A)
If A and B are independent, what is the formula for P(A and B)
P(A and B) = P(A) * P(B)
When events are mutually exclusive, P(A or B) =
P(A) + P(B)
What is the formula for complementary events
P(a) + P(not a) = 1
when n is multiplied/ divided by every number in the dataset, what happens to the standard deviation
SD2 = SD1 *n
What is a multiple?
The product of that number and any integer
What is independence in probability?
Two events are independent when the incidence of one event does not affect the probability of the other event occuring
a to b is equivalent to
a/b
a is what percent of b translates to
a/b * 100 = ?
median formula in even # of terms:
average of n/2 and (n+2)/2 position
1 to a/b is equivalent to
b to a
sqrt(a+b) _______ sqrt(a) + sqrt(b)
does not equal
A perfect square will have only _______ exponents of its prime factorization
even
even + even
even
even - even
even
even x even
even
even x odd
even
odd + odd
even
odd - odd
even
odd x even
even
an open circle means that value is ___________
excluded
formula to calculate range
highest number in a set - lowest number in a set
mean = median when
in any evenly spaced set, the mean of the set is equal to the median of the set
a closed circle means that value is ___________
included
when n is multiplied/ divided by every number in the dataset, what happens to the mean
mean2 = mean1 *n
when n is added / subtracted to every number in the dataset, what happens to the mean?
mean2 = mean1 +- n
when n is multiplied/ divided by every number in the dataset, what happens to the median
median2 = median1 *n
when n is added / subtracted to every number in the dataset, what happens to the median
median2 = median1 +- n
when n is multiplied/ divided by every number in the dataset, what happens to the mode
mode2 = mode1 *n
when n is added/ subtracted to every number in the dataset, what happens to the mode
mode2 = mode1 +- n
what is a mode
most frequently occurring value
what is the basic combination formula
n! / ((n-k)!k!)
what is the basic permutation formula
n! / (n-k)!
in the equation (n/k) what is n
number of objects
in the equation (n/k) what is k
number of objects selected
What is a factor?
numbers you multiply together to get another number
even + odd
odd
odd x odd
odd
when n is multiplied/ divided by every number in the dataset, what happens to the range
range2 = range1 *n
when n is added / subtracted to every number in the dataset, what happens to the standard deviation
sd2 = sd1
non-perfect squares to memorize
square root of: 2, 3, 5
formula for average
sum of terms / number of terms
In the formula (k-1)! what is k?
the number of terms to be arranged in a circle
A perfect cube will have only exponents divisible by _______ in its prime factorization
three (3)
x is n percent of y
x = (n/100)*y
x percent of z translates to
x/100 * (z)
(x^a)(x^b)
x^(a+b)
(x^a)/(x^b)
x^(a-b)
b-root(x^a)
x^(a/b)
(x+y)^2
x^2+2xy+y^2
(x-y)^2
x^2-2xy+y^2
(x^a)^b
x^ab
(x+y)(x-y)
x²-y²