133 terms

GMAT

STUDY
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11^2
121
12^2
144
13^2
169
14^2
196
15^2
225
25^2
625
2^6
64
2^7
128
2^8
256
2^10
1024
1/6
.166
1/8
.125
1/12
.083
1/9
.11
1/11
.09
Divisibility Rule for 3
If the sum of the digits is a multiple of 3
Divisibility Rule for 4
Last two digits are divisible by 4
First 15 Prime Numbers
2,3,5,7,11,13,17,19,23,29,31,37,41,43,47
Dividing by a negative exponent..
makes a number larger
Multiplying by a negative exponent...
makes a number smaller
2^9
512
When cross multiplying put the answer by the
Numerator (top number)
6 division rule
Divisible by both 2 and 3
Reciprocal
Product of the two fractions equals 1
If you increase a numerator
The number increases
Compound Interesr
P(1 + r/n)^nt
Rate Time Work equation
Rate*Time=work
30-60-90 proportions
X:X*root(3):2x (opposite 30, opposite 60, hypotenuse)
Circumference to diameter
C = 2(pi)r
Is neither singular or plural
Singular
Proper use of correlate
Correlates with
1/50
.02
1/25
.04
1/20
.05
3/8
.375
5/8
.625
5/6
.833
7/8
.875
Root 2
1.4
Last digit short cut
Multiply the digits of relevant numbers
16^2
256
Root 3
1.7
Root 5
2.25
4^3
64
5^3
125
X^2 - Y^2
(X + Y)(X - Y)
X^2 + 2xy + Y^2
(X + Y)^2
X^2 - 2xy + Y^2
(X - Y)^2
XY > O implies
XY are both positive or both negative
XY < O implies
X and Y are different signs
X^2 - X < 0
0 < x < 1
Quadratic
X = -b +/- root(b^2 - 4ac) / 2a
Proportion
X / Y
Inverse Proportion
XY
Exponential groeth
Y = Y*k^t
Simple interest
P(1 + rt/100)
45 45 90 ratio
X:X:Xroot(2)
Rhombus
Opposite angles equal all sides equal
Parallelogram
Opposite sides and angles equal
Trapezoid
One pair of opposite sides parallel
Angles of shape
(N-2)*180
Trapezoid Area
(B1 + B2) * H / 2
Area of Rhombus
Diagonal1*diaganol2/2
Triangle inequality law
Sum of any two sides are bigger than the third, third must also be bigger than the difference of the two
Common triangle combos
3-4-5 (6-8-10, 9-12-15, 12-16-20)
5-12-13 (10-24-26)
8-15-17
Diagonal equation square
D = s*root(2)
Cube diagonal equation
D = s*root(3)
17^2
289
Arc length
Angle/360dpi
Inscribed angle vs. arc
.5 *arc angle
Cylinder surface area
2*pi*r^2 + 2pipi*r^2 + 2*pi*r*h
Volume of a cylinder
Pir^2h
How to arrange group of n objects without restrictions
N!
How to handle a group of n size with m and omembers the same
N!/M!*O!
P(a) + p(not a)
Equals 1
Divisibility rule 8
Divisible by 2 3 times or last 3 digits divisible by 8
Divisibility 9
Sum of digits are divisible by 9
Factor foundation rule
If b is a factor of a and c is a factor of b, then c is also a factor of a
Dividend remainder equation
A/B = multiple + remainder/B
Sum of two odds vs mult of two odds
Even and odd
Standard deviation
Root of the sum of the difference between the items of the set and the mean squared divided by the number of elements
GCF
Product of overlapping primes
LCF
Product of all primes in diagram
GCM of m and n x LCF of m and n
Equals m x n
How do you determine prime factor length?
Adding up exponents
How many factors do perfect squares have
Odd number
Prime factorization of a perfect square contains..
Only even powers
How do you determine any higher level perfect number
Factors are divisible by the level of perfect it is (perfect cubes, 3, etc)
For evenly spaced sets mean and median are
Equal, the average of the first and last number
Sum of a set of consecutive integers equals
Average time number of items
The product of k consecutive integers is divisible by
K!
A sum of k integers if k is odd is
A multiple of k
A sum of k integers if k is even is
Not a multiple of k
Exterior angle equals
Sum of non-adjacent angles
What type of quadrilateral has the largest area with a given perimeter
Square
Mid point between A(x,y) and B(x,y)
X + X / 2, Y + Y/2
If you add or subtract a non multiple of n to a multiple of n
The result is not a multiple of n
Mode is
Observation that shows up most
Neither nor verb agreement
Agrees with the closest subject
Collective nouns are
Considered singular
The boy, along with his friends, - is?
Singular
Can THAT modify people
No, use who or whom
We had an arrangement WHERE or IN WHICH
IN WHICH
Terminating decimal must include
2^x or 5^x or both
Can a perfect square be expressed as the product of an even number of positive prime factors
Yes 5x5
If x > O then
|x| = x
If x < 0 then
|x| = -x
When testing inequalities with powers remember
Test fractions and negatives
Think of one combinatorial problem where order matters and one where it does not. What do you divide by if it does not?
The factorial number of choices
For a definitional sentence use what tense
Simple present not present progressive
What tense should be used to indicate future action
Simple future (will x) not present progressive (is xing)
Present perfect is
An action that happened in the past and continues to today (can also have an impact currently)
Use Past Perfect when
You need to clarify the timing between two past events, not when one event is obvious or continued effect in the past
What are the pairs of tenses for reporting
Present + future and past + conditional
Command verbs that take the infinitive
Advise, allow, forbid, persuade, want
Command verbs that take either infinitives or command subjunctives
Ask, beg, order, prefer, urge, require
Past progressive can be used for
Background state of affairs "he was wearing a helmet, so he did not get hurt"
Present tense of subjunctive
Looks like past simple (swallowed, ate, etc)
Is 0 positive or negatice
Neither
Comparison signals
As, as blank as, as much as, as little as, more than, less than, different than, in contrast to, the same as
Like must be followed by
Nouns pronouns or noun phrases not a clause
As can be followed by
Either a noun alone or a clause
Comparisons must be
Structurally similar in terms of grammar
When is 1/x > 1/y
When x and y are positive and x < y
When is 1/x < 1/y
When x is negative and y is positive and x < y
If both sides are negative, what should you do when you square an inequality
Flip it
If both sides are positicd, what should you do when you square an inequality
Nothing
Can you square an inequality with one side positive and the other negative
No
Can less be used with countable items
No, use few instead (except for units which take less I.e dollars)
How many things can between modify
2 for 3 use among
Which is singular "a number of" or "the number of"
The number ofp
When finding the length of an arc from an angle you use an angle from x
Center of the circle, which is 2x an angle from the circumference
Ratio of sides and areas for similar triangles
A:B and a^2:b^2
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