Question 1071490

His total score for the first 6 exams is  6*57.5 = 345

His new mean score after the 7th exam is therefore   (345+45)/7 = 55.714

(In the final calculation, we divide by 7 because the 345 represents 6 exams while the 45 represents 1 exam, for a total of 7 exams.)