31 Answered Questions for the topic Prime Numbers
How would you factorise an equation with no factors?
So I need to factorise the equation: x2-5x-7=0I have learned how to do this before, but can’t for the life of me remember or find the theory for it.Thanks if you can lend me a hand!
Quadratic equations: variables in exponents using prime numbers
I can't find the solution, could I get some help please?22x - 24.2x + 128 = 0 thanks for the help
Composite prime numbers
What composite numbers less the 20 have more than five factors
Are all highly composite numbers even?
A highly composite number is a positive integer with more divisors than any smaller positive integer. Are all highly composite numbers even (excluding 1 of course)? I can't find anything about this... more
Can it be proven/disproven that there are highly composite numbers that prime-factorize into larger primes such as $9999991$?
Of course, following the rules found by Ramanujan, such a highly composite number would need to factorize into all primes ascending up to 9999991 (with descending powers as the primes progress) so... more
When is $4n^4+1$ prime?
Find all natural numbers $n$ such that $4n^4+1$ is prime. $4n^4+1$ is obviously prime when $n=1$. But can we prove that no other $n$ works?
How many primes do I need to check to confirm that an integer $L$, is prime?
I recently saw the 1998 horror movie "Cube", in which a character claims it is humanly impossible to determine, by hand without a computer, if large (in the movie 3-digit) integers are prime... more
Is 440 a factor of 72840?
I would like to know how to solve the following question: Is 440 a factor of 72840? I would have thought that this involves dividing 72840 by 440 and seeing if it produces an integer. However, the... more
If n!+1 is prime, is n prime?
Just wondering if this is true or false!
Prime Numbers Prime Factorization
Maritza remembers her PIN because it is between 1000 and 1500 and it is the product of two consecutive prime numbers. What is her PIN
Marie remembers her PIN because it is between 1000 and 1500 and it is the product of two consecutive prime numbers. What is her PIN?
Put a check by all the prime numbers.
why cant 7 be the difference of any prime number?
i have to prove why 7 cant be the difference of any prime number
if j represents the smallest prime number greater than 24, and c represents the largest prime number less than 100, what is the value of c-j
please show me steps to this
Are any prime gaps end larger than the square of the prime?
I am not trained in mathematics at all and I was thinking about a certain problem. I'm not sure if there's a name for this problem or how to search for work done on it before. Assume the... more
Prime Numbers Real Numbers
a boy with a collection of marbles realises that if he makes a group of five or six marbels at a time there are always two marbles left can you explain why the
confused between concept of real numbers and prime number used in the question
A teacher divides the students into three groups for a project. Each group has the same number of students. Is the total number of students prime or composite
is there an easier way to find out how many prime numbers are under 100 without going through each number? Thanks!
Prime number word problem..
Brenda is thinking of a prime number between 40 and 50. Josh is thinking of a prime number between 10 and 20. The difference between the two numbers is 26. What are the two numbers?
Find the smallest possible value of the whole number
Find the smallest possible value of the whole number "y" such that the product of "y" and 6600 is a square number.To make two identical numbers from 6600 x Y, we add prime numbers to the product.
Which number is prime? 26 or 9 or 5 or 6
which number is prime?
Which list contains only one prime number ? (A) 3,4,5,6 (B) 6,9,10,11 (C) 4,10,12,21 (D) 7,11,13,17......
I got this question when I was doing my SOF Olympiad Practice.The Solution say's the answer is (B).But I don't understand how.....
Prime Numbers Probability
Probabilty for first 10 prime numbers pulled out of a hat
Each of the first ten prime numbers is written on an individual piece of paper and put into a hat. If two are drawn at once, so that means without replacement, what is the probability that the sum... more
Weird prime numbers question
The sum of 2 postive prime numbers is a prime number and 3 times that sum is an odd number. Which of the following prime numbers must be one of the original prime... more
Prime Numbers Maths
Show that this equation is true
It is given that p is a prime number and p > 5. a) Show that p= 6n + 1 or p = 6n + 5 for some positive integer n. b) Hence, show that p2 + 2 is divisible by 3. How can I 'show that'? With... more
Which of the following is not a prime number? A. 11 B. 19 C. 5 D. 24
-Which of the following is not a prime number? A. 11 B. 19 C. 5 D. 24