It is 75.
17 and 3 are two prime numbers whose sum is 20. Their product is 51.
17
(2,3) and (2,5) are the two pairs such that the sum of their elements is a prime number.
The largest prime less than 20 is 19. The largest prime over 60 is 61. The sum of these two numbers is 80.
It is 75.
3 + 17 = 20
They are: 2+7+11 = 20
17 and 3 are two prime numbers whose sum is 20. Their product is 51.
3 and 17
600 * * * * * It is, in fact, 639
-20
17
It is 1.
(2,3) and (2,5) are the two pairs such that the sum of their elements is a prime number.
The sum is: 23+29+31+37 = 120
The largest prime less than 20 is 19. The largest prime over 60 is 61. The sum of these two numbers is 80.