5 students of a class have an average height 150 cm and variance 18 cm2. A new student, whose height is 156 cm, joined them. The variance (in cm2) of the height of these six students is:

5 students of a class have an average height 150 cm and variance 18 cm

1.	5 students of a class have an average height 150 cm and variance 18 cm2. A new student, whose height is 156 cm, joined them. The variance (in cm2) of the height of these six students is:
A.	16
B.	22
C.	20
D.	18
Answer» D. 18