Given data:
The number of hour Stacy studied maths is 2/6 hour.
The number of hour Stacy studied science is 3/6 hour.
The total number of hours Stacy studied in 5 days is,
[tex]\begin{gathered} 5(\frac{2}{6}+\frac{3}{6})=5\times\frac{5}{6} \\ =\frac{25}{6} \end{gathered}[/tex]Thus, the total number of hours Stacy studied in 5 days is 25/6 hours, so option (D) is correct.