Question

If mean of 12 values is 19.25. If one more value is included then the mean 13 becomes 20 . Find 13 th value.

Answer 1

The 13th value is 29.

• Given,

              Mean of 12 values = 19.25

              (sum of 12 values)/12= 19.25

               sum of 12 values = (19.25)(12)

                                            = 231    --------(1)

• Let the 13th value be 'x'

              Mean of 13 values = 20

              (sum of 13 values)/13 = 20

              (sum of 12 values + x) = (20)(13)

               231 + x = 260             [from (1)]

                         x = 260 - 231

                        x = 29

∴ The 13th value is 29.