Question

what is the fourth number of 12 48 50 if the mean is 30

Answer 1

(12 + 48 + 50 + x)
------------------------ = 30
        4


(110 + x)/4 = 30

110 + x  = 30 x 4

110 + x = 120
x = 120 -110

x = 10

fourth number should be 10

hope this helps