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The mean of a set of 10 numbers is 18.When two numbers 2k and 5k are added,the mean increases by 1.Find the value of k.

Respuesta :

mean = total / frequency
18 = total/10
total = 18 x 10 = 180

(180 + 2k + 5k)/12 = 19
(180 + 7k) = 19 x 12 = 228
7k = 228 - 180 = 48
k = 48/7 = 6.857