Two prime numbers can have only one sum, not three different sums!
391
37 + 3
17, 23.
3 + 37 = 4011 + 29 = 4017 + 23 = 40
Three prime numbers whose sum is 42 are 23, 17 and 2
31 is the only prime number between 30 and 40
120
23 times 5
68
The prime numbers between 40 and 50 are 41, 43, 47. So their sum is 131.
2, 7 and 31 add up to 40.
The sum is: 23+29+31+37 = 120