The average height of 12 students of a class is 157.5 cm. If one more student joins the average height becomes 156.6 cm. the height of the new student is?

 145.8

Let the average height of 13 student = 156.6

Absolute average height of 12 students decreased by = (157.5 -156.6) × 12 = 0.9 × 12 = 10.8

Therefore,

Height of the 13th student = 156.6 - 10.8 = 145.8