Posted by Jane on .
Andrew arranged the number 1, 2, 3, ...11, 12 into six pairs so that the sum ofany two numbers in a pair is prime and no two of these primes are equal. find the primes and the pairs

Maths 
drwls,
I had to solve this by "trial and error" and finally came up with this. There many be other solutions.
1 + 4 = 5
2 + 5 = 7
3 + 8 = 11
6 + 7 = 13
9 + 10 = 19
11 + 12 = 23
Other primenumbersum combinations possible would have been 3 and 17, but by forming them I had to use numbers twice or get duplicate sums. 
Maths 
Rosie,
(5,8);(3,2);(1,6);(9,10);(4,7);(11,12).
5+8=13
3+2=5
1+6=7
9+10=19
4+7=11
11+12=23
Hope that helps!!!!! :) 
Math 
Anonymous,
1+2=3
3+4=7
5+8=11
6+7=13
9+10=19
11+12+23