a) do chores 13 + 3 = 16
answer: 16 students
b) this is
[tex]\frac{chores\text{ and allowance}}{\text{chores}}=\frac{13}{16}=0.8125[/tex]answer: 0.81
c) this is
[tex]\frac{\text{no chores and no allowance}}{total}=\frac{4}{25}=0.16[/tex]answer: 0.16
d) this is
[tex]\frac{no\text{ chores and allowance}}{no\text{ chores}}\times100=\frac{5}{9}\times100=\frac{500}{9}=55.55[/tex]answer: 55.55%