Is it possible to write down 1,2,3..100 in some order (one after an other), such that the sum of any two adjacent numbers is a prime number?
Is it possible to write all integer from 1 to 10 in a row in some order such that any two adjacent number add up to a prime number ?
A five-digit number is formed using digits 1,3,5,8 and 9 without repeating any one of them. What is the sum of all such possible numbers?