The average of ten numbers is X and the average of five of these is Y.If the average of the remaining five is z, then
Choose the correct choice from the following answers:
A) x = y+z
B) 2x = y+z
C) x = 2y+2z
D) none of the above
E) Cannot be determined
Explanation :   Clearly, we have x =(5y+5z/10)   or   2x = y + z   Answer : 2x = y+z
<result>B</result>
The average of ten numbers is X and the average of five of these is Y.If the average of the remaining five is z, then