Five numbers have a mean of 8. A sixth number is added and the mean of all six numbers becomes 7. Which statements about this change are true? Select all that apply.

توضیح

Five numbers averaging 8 total 40, and six numbers averaging 7 total 42, so the number that was added is 42 - 40 = 2. A mean falling by 1 does not make the added number 1, because the new value has to cover a shortfall of 1 spread across all six numbers, which is why comparing the two totals is the reliable route.