The numbers are in an arithmetic sequence (common difference = 6). Since there are 5 of them, their mean is the middle number: 79.
79
53 59 61 67 71 73 79 83 89 97.
61, 67, 71, 73, 79, 83, 89, 97, so 79 is nearest
47, 53, 59, 61, 57, 71, 73, 79
Any number except 61 67 71 73 and 79 which are prime numbers
Add them up. 61 67 71 73 79 83 89 97
53 59 61 67 71 73 79 83 89 97
53 59 61 67 71 73 79 83 89 97.
67, 71, 73, 79, 83, 89
61 67 71 73 79.
They are: 67, 71, 73, 79
61, 67, 71, 73, 79.