-4
8, 9, 11 and 12
2
It is 10.
The fourth number is 10. The sum of the four numbers is: 12 + 50 + 48 + fourth_number = fourth_number + 110 Mean = sum_of_numbers / how_many_numbers → sum_of_numbers = mean × how_many_numbers = 30 × 4 = 120 But from above: sum = fourth_number + 110 = 120 → fourth_number = 120 - 110 = 10
12 10 10 10
The numbers are -12, -11, -10 and -9.
9 + 10 + 11 + 12 = 42
The numbers are 9, 10, 11 and 12.
four and sixteen16 - 4 = 1216 + 4 = 20 then 20 / 2 = 10Half of 12 is 6, therefore the two numbers 10 - 6 = 4 and 10 + 6 = 16 will have a mean of 10 and a range of 12.Further numbers can be added between 4 and 16 as long as their mean is still 10, eg the data sets:{4, 16}{4, 10, 16}{4, 8, 12, 16}{4, 8, 10, 12, 16}{4, 7, 9, 14, 16}all have a mean of 10 and a range of 12. There is an infinity of such sets.
(10, 12, 12, 13, 13)
The numbers are -12, -11, -10, and -9.
6 + 10 + 14 + 18 = 48/4 = 12 The average of the four numbers is 12.