Subject: mathqa
Question: the average height of 20 students in a class was calculated as 175 cm . it has later found that the height of one of the students in the class was incorrectly written as 151 cm whereas the actual height was 131 cm . what was the actual average height of the students in the class ?
Option: 
A: 171 cm
B: 170 cm
C: 174 cm
D: 173 cm
Answer: C