If the mean of numbers 28, x, 42, 78 and 104 is 90, then what is the mean of 128, 255, 511, 1023 and x?
Choose the correct option:
A) 395
B) 275
C) 355
D) 423
E) 365

Rationale: the mean of numbers 28 , x , 42 , 78 and 104 is 62 : 28 + x + 42 + 78 + 104 = 90 * 5 - - > x = 198 ; so , the mean of 128 , 255 , 511 , 1023 and x is ( 128 + 255 + 511 + 1023 + 198 ) / 5 = 423 . answer : d .
Answer: D