Problem: 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 ?
Rationale: "the total height was 20 cm too much . the average height should be reduced by 20 cm / 20 = 1 cm the answer is a ."
annotated_formula: divide(subtract(multiply(20, 175), subtract(151, 131)), 20)