A group consists of a certain number of individuals. If two

Solution

Let the number of people in group and average weight of group be 'n' and 'm' kg, respectively.
So, mn - 2 X 59 = (n - 2) X (m - 1)
Or, mn - 118 = mn - n - 2m + 2
Or, 2m + n = 120 --------- (I)
And, mn - 3 X 60 = (n - 3) X (m - 2)
Or, mn - 180 = mn - 2n - 3m + 6
Or, 2n + 3m = 186 --------(II)
On solving 3 X equation I - 2 X equation II,
We get, 3 X (2m + n) - 2 X (2n + 3m) = 3 X 120 - 2 X 186
Or, 6m + 3n - 4n - 6m = 360 - 372
Or, 'n' = 12