84.4
The numbers 71, 73, 79, 83, 89 and 97 are prime.
71 73 79 83 89
71 73 79 83 89 97.
71 73 79 83 89.
71 73 79 83 89.
71 73 79 83 89.
They are: 71, 73, 79, 83 and 89
71 73 79 83 89 97.
71 73 79 83 89 97.
71, 73, 79, 83, 89, and 97
71, 73, 79, 83, 89.
71 73 79 83 89 97.