10. On standard dice the total number of pips on each pair of opposite faces is 7 . Two standard dice are placed in a stack, as shown, so that the total number of pips on the two touching faces is 5 .
What is the total number of pips on the top and bottom faces of the stack?
A 5
B 6
C 7
D 8
E 9
Solution: $\mathbf{E}$
The total number of pips on the top and bottom faces of the two dice is $7+7=14$. As there is a total number of 5 pips on the touching faces, there are $14-5=9$ pips altogether on the top and bottom faces of the stack.