From the question, It takes Ary an hour to write one thank you card.
So, the rate at which she writes the thank you card is;
[tex]\text{Rate R}=1\text{ card/hour}[/tex]To determine the number N of thank you card she would write in 8 hours.
[tex]N=R\times T[/tex]Where;
R is the rate = 1 card/hour
T is the time taken = 8 hours
Substituting the values we have;
[tex]\begin{gathered} N=1\text{ card/hour}\times8\text{ hours} \\ N=8\text{ cards} \end{gathered}[/tex]The number of thank you cards she write is 8 cards
