Provide your best answer for the following math problem. Give ONLY the answer, no other words or explanation.
For example:

Answer: <most likely answer, as short as possible; not a complete sentence, just the answer!>.

The problem is: in arun ' s opinion , his weight is greater than 64 kg but leas than 72 kg . his brother does not agree with arun and he thinks that arun ' s weight is greater than 60 kg but less than 70 kg . his mother ' s view is that his weight can not be greater than 67 kg . if all of them are correct in their estimation , what is the average of diferent probable weights of arun ?
65.5 kg
66.67 kg.