[tex]\begin{gathered} \text{Percentage change=}\frac{\text{difference}}{previous\text{ value}}\times100 \\ \text{Difference}=11,\text{ Previous value=74} \\ \text{Percentage change=}\frac{11}{74}\times100 \\ \text{Percentage change=}\frac{1100}{74} \\ \text{Percentage change}=14.8648\ldots \\ \text{Percentage change=15 (rounded to the nearest whole percent)} \end{gathered}[/tex]
Part B;
It is an increase of 15% from 74 hours to 85 hours