Problem: the average height of 30 students in a class was calculated as 177 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 106 cm . what was the actual average height of the students in the class ?
Rationale: "the total height was 45 cm too much . the average height should be reduced by 45 cm / 30 = 1.5 cm the answer is b ."
annotated_formula: divide(subtract(multiply(30, 177), subtract(151, 106)), 30)