In Arun's opinion, his weight is greater than 65 kg but less than 72 kg. His brother doest 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 cannot be greater than 68 kg. If all are them are correct in their estimation, what is the average of different probable weights of Arun?

Explanation:-

Let Arun's weight by X kg.
According to Arun, 65 < X < 72
According to Arun's brother, 60 < X < 70.
According to Arun's mother, X <= 68
The values satisfying all the above conditions are 66, 67 and 68.
$$\eqalign{ & \therefore {\text{Required}}\,{\text{average}} \cr & = \left( {\frac{{66 + 67 + 68}}{3}} \right) \cr & = \left( {\frac{{201}}{3}} \right) \cr & = 67\,kg. \cr}$$