12. The mean of a set of 8 numbers is 12 . Two numbers with a mean of 18 are removed from the set. What is the mean of the remaining 6 numbers?
A 6
B 7
C 8
D 9
E 10
Solution
$\mathbf{E}$

The total of the set of 8 numbers is $8 \times 12=96$. The total of the two numbers removed is $2 \times 18=36$. Therefore the total of the 6 remaining numbers is $96-36=60$. Hence the mean of the 6 remaining numbers is $60 \div 6=10$.