5. All old Mother Hubbard had in her cupboard was a Giant Bear chocolate bar. She gave each of her children one-twelfth of the chocolate bar. One third of the bar was left. How many children did she have?
A 6
В 8
C 12
D 15
E 18
Solution: B
One third of the bar was left, so Mother Hubbard's children ate two-thirds of the bar. Since they ate one-twelfth of the bar each, Mother Hubbard had
$\frac{2 / 3}{1 / 12}=\frac{2}{3} \times \frac{12}{1}=\frac{24}{3}=8$ children.