18. Twelve girls met in a cafe. On average, they ate $1 \frac{1}{2}$ cupcakes each, although no cupcakes were actually divided. None of them ate more than two cupcakes and two of them ate no cupcakes at all. How many girls ate two cupcakes?
A 2
B 5
C 6
D 7
E 8
18. E The total number of cupcakes eaten by the girls is $12 \times 1 \frac{1}{2}=18$. Two girls ate no cakes so the 18 cupcakes were eaten by 10 girls. Since no-one ate more than two cupcakes, the maximum number of cupcakes the 10 girls could have eaten is $10 \times 2=20$. For every girl who eats only one cupcake, the total of 20 is reduced by 1 . Hence the number of girls who ate only one cupcake is $20-18=2$ and hence the number of girls who ate two cupcakes is 8 .