A class contains 10 girls and 20 boys. The average height of the girls is 1.58m and the average height of the boys is 1.67m . Calculate the average height of the student in the class.

Average height of the students in the class = (10 x 1.58 + 20 x 1.67) / (10 + 20) = 1.63m

I got 1.64 using the numbers given