QUANT facts Flashcards
3 ^ k means…
how many 3s are there?
“if x is a multiple of 7, and y is a multiple of 7, then x +y is a multiple of?”
If two numbers are both multiples of the same number, their SUM is also a multiple of that number
The greatest POSSIBLE factor of A and B is…
The positive distance between them.
ex: | A - B | = x
two numbers that are X apart may both be multiples of X, but cannot be multiples of any number larger than X.
(a + b) ^2 =
a^2 + 2(a)(b) + b^2
(a - b) ^2 =
a^2 - 2(a)(b) + b^2
(a^2 - b^2) =
(a-b) (a+b)
when are the mean and the median always equal?
In a set of consecutive integers
Divisibility fact about a set of “n” consecutive integers
at least one of the numbers in the set is divisible by “n”
If “n” number of consecutive integers is even
Then sum is NOT a multiple of “n”
AND
The range is odd
If “n” number of consecutive integers is odd
Then sum IS a multiple of “n”
AND
The range is even
Two ways to calculate percent change
(New - Old) / Old
OR
(amt of change / starting amount) x100
Trailing Zeros Formula
ex: how many zeros are in the end of 32!
n/5 + n/5^2
ex: 7 zeros are in the end of 32!
xy > 0
signals?
x and y are either both positive or both negative
Overlapping Sets Formulas (3 different ones)
A+B - Both + Neither
A+B+C - (sum of 2 groups) + (all 3) + Neither
A+B+C - (sum EXACTLY both) - 2(all 3) + Neither
Ratio or fraction like this signals what 2 two things?
A:B = 5:2
or
A/B = 5/2
1- that A and B have the same sign
2- that A has a larger magnitude than B (aka, A will be further from 0 than B will be)