I have one more problem that i am stuck on if anyone could show me how to get the answer to this one also.. thanks
Prime numbers that differ by 2 are called twin primes. Examples are 3 and 5, 5 and 7, and so on. Which pair of numbers are twin primes?
109 and 111
61 and 63
13 and 15
41 and 43
2006-11-22 01:41:24 · 8 answers · asked by CrazyBlueEyedGirl13 1 in Science & Mathematics ➔ Mathematics
Thank you...you guys are so much help on here... thanks again
2006-11-22 01:57:52 · update #1
111 is divisible by 3 (plus others) so is not a prime
63 is divisible by 3 (plus others) so is not a prime
15 is divisible by 3 (plus others) so is not a prime
41 and 43 are twin primes
2006-11-22 01:44:25 · answer #1 · answered by Tom :: Athier than Thou 6 · 0⤊ 0⤋
To answer this problem you have to know how to factor.
Each of the pairs differ by two, if you can find at least one of each pair that can be factored then they are not twin primes.
Quick rules of thumb to identify non-prime numbers:
number ends in an even number, then is divisible by 2
sum of numbers is a multiple of 3, then is divisible by 3 (111, 63, 15 are not prime)
number ends in a 5 or a 0, divisible by 5 (15 is not prime)
2006-11-22 09:49:41 · answer #2 · answered by Anonymous · 0⤊ 0⤋
41 and 43. There is no formula. A prime number can only be divided evenly by 1 and itself. Since the only pair that meets this criteria is 41 and 43 that is the answer.
2006-11-22 09:51:44 · answer #3 · answered by Anonymous · 0⤊ 0⤋
41 and 43
2006-11-22 09:56:11 · answer #4 · answered by english_improve 3 · 0⤊ 0⤋
41 and 43
2006-11-22 09:43:03 · answer #5 · answered by 7 · 0⤊ 0⤋
only 41 and 43 pair is twin prime
because 111 has a factor 3 so 1st one is not
63 has a factor 3 so 2nd one is not
15 has a factor 3 so 3rd one is not
2006-11-22 11:03:48 · answer #6 · answered by Mein Hoon Na 7 · 0⤊ 0⤋
41 and 43 definitely n_n
2006-11-22 09:49:01 · answer #7 · answered by jamezu 2 · 0⤊ 0⤋
hotmath.com will answer for free
2006-11-25 18:20:45 · answer #8 · answered by Talking Hat 6 · 0⤊ 0⤋