Jake scored a 94 on his last quiz, which is exactly 2 standard deviations above the mean of his class. If the standard deviation was 3, what was the mean grade on the quiz

Three numbers x, y, and z are in the ratio 2: 7: 8. if 12 is subtracted from y, then three numbers form a geometric sequence (in the order x, y–12, z). find x, y, and z. there are 2 sets.