Present ages of the five family members: 40, 15 , 20 , 35 and 60
Arithmetic mean=Sum of all observationsTotal number of observations
=40+15+20+35+605
=1705 =34
Ages of the members two years from now : 42, 17, 22, 37 and 62.
Mean of their ages two years from now is calculated as follows:
New mean=42+17+22+37+625
=1805=36
Hence, two years from now, the mean age will increase by 2 years.