Explanation:
the average is the sum of all data points divided by the number of data points.
so, with 8 students the average is
(x1 + x2 + x3 + ... + x7 + x8)/8 = 60 in
that means the sum of the data points is
x1 + x2 + x3 + ... + x7 + x8 = 60×8 = 480 in
now, we take 2 students out leaving us with 6 data points, and the average there is
(x1 + x2 + x3 + x4 + x5 + x6)/6 = 62 in
that means the sum of the data points is
x1 + x2 + x3 + x4 + x5 + x6 = 62×6 = 372 in
so, in total, when the 2 students left, the class lost
480 - 372 = 108 inches
that means Merrilyn and Max are together 108 inches tall.
and their average height is therefore
(x1 + x2)/2 = 108/2 = 54 inches