QUANT Flashcards
Product of k Consecutive Intergers is always divisible by _____
k! (k factorial)
According to the Factor Foundation Rule, every number is divisible by all the factors of its factors. If there is
always a multiple of 3 in a set of three consecutive integers, the product of three consecutive integers will
always be divisible by 3. Additionally, there will always be at least one multiple of 2 (an even number) in
any set of three consecutive integers. Therefore, the product of three consecutive integers will also be
divisible by 2. Thus, the product of three consecutive integers will always be divisible by 3!: 3 × 2 × 1 = 6.
Sum of a set of ODD number of consecutive integers is ALWAYS_____
a multiple of the number of items
————————-
Sum = #of items x Avg
This is true because the sum
equals the average multiplied by the number of items. The average of {13, 14, 15, 16, 17} is 15, so
15 × 5 = 13 + 14 + 15 + 16 + 17.
n-2,n-1, n, n+1, n+2
sum of above -> divisible by n!!
Sum of a set of EVEN number of consecutive integers is _____
NEVER divisible by the number of items
————
This is true because the sum equals the average multiplied by the number
of items. For an even number of integers, the average is never an integer, so the sum is never a multiple
of the number of items. The average of {8, 9, 10, 11} is 9.5, so 9.5 × 4 = 8 + 9 + 10 + 11. That is,
8 + 9 + 10 + 11 is NOT a multiple of 4.
———-
n-2, n-1, n, n+1
Sum of above can’t be divided by n
√A = ____
A ^(1/2)
∛A =
A ^ (1/3)
Range
Max-Min
Mean
Quantity X Quality
—————————
Quantity
Standard Deviation
Average distance from the mean
Data Sufficiency Question (Value)
If the question asks for the value of an unknown (e.g., What is x?).
Sufficient -> provides exactlyone possible value.
Not Sufficient -> provides more than one possible value.
Data Sufficiency Question (YES/NO)
The question asks whether a given piece of information is true (e.g., Is x even?).
Most of the time, these will be in the form of Yes/No questions.
Sufficient -> Always Yes or Always No.
Not Sufficient -> answer isSometimes Yes, Sometimes No.
If the starting fraction is less than 1, the fraction gets ___ to 1 (it in___ as you add the same number to
the top and bottom
Adding the exact same number to both the numerator and the denominator brings the fraction ___ to 1,
regardless of the fraction’s value.
Closer; increase
2/3 — closer to one when add 80 to both —-> 82/83
If the starting fraction is greater than 1, the fraction gets ___ to 1 (it in___ as you add the same number to
the top and bottom
Closer; decrease
3/2 — add 80 to both -> 83/82
Number decreased
Arithmetic Strategy
- Testing cases (question: what must be @@? What could be @@? @@-> true, or false or a certain characteristic)
- Choose smart numbers
- Work backwards (start with B, too large then A and move on. If wrong, go to D, too large? C! Too small? E!)
