Quant Flashcards
What is the formula for sum of consecutive integers
Sum=average*number of terms
Average=(first+last)/2
Number of terms=last-first+1
How would you solve how many integers are there from 14 to 765, inclusive?
(Last-first+1)
765-14+1
How would you solve all the even integers between 12 and 24, inclusive?
((Last-first)/increment)+1
((24-12)/2)+1
How would you solve how many multiples of 7 are there between 10 and 40?
Could find least multiple of 7 and highest multiple of 7 then solve.
((35-14)/7)+1
An integer is divisible by 2 if…
The integer is even
An integer is divisible by 3 if…
The sum of the integer’s digits is divisible by 3
An integer is divisible by 4 if
The integer is divisible by 2 twice or if the last two digits are divisible by 4
An integer is divisible by 5 if
The integer ends in 0 or 5
An integer is divisible by 6 if
The integer is divisible by 2 and 3
An integer is divisible by 8 if
The integer is divisible by 2 three times or if the last three digits are divisible by 8
An integer is divisible by 9 if
The sum of the integer’s digits is divisible by 9
The first 17 prime numbers are…
2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59
The product of k consecutive integers is always divisible by…
k factorial (k!)
Example a product of set of 4 consecutive numbers will be divisible by 4!—4x3x2x1=24
Odd+odd=
Even
Even+even=
Even
Even+odd=
Odd
Odd-odd=
Even
Even-even=
Even
Even x even=
Even
Even x odd=
Even
Odd x even=
Even
Odd x odd=
Odd
Even/odd=
Even