1. **State the problem:** Su-Lin worked different hours on Monday, Tuesday, Wednesday, and Thursday. We need to find her total hours worked for the week and then find the fraction of overtime hours (3 hours) out of the total hours worked. 2. **Add the hours worked each day:** Monday: $5 \frac{1}{2} = 5 + \frac{1}{2} = \frac{10}{2} + \frac{1}{2} = \frac{11}{2}$ hours Tuesday: $4 \frac{1}{2} = 4 + \frac{1}{2} = \frac{8}{2} + \frac{1}{2} = \frac{9}{2}$ hours Wednesday: $7 \frac{1}{4} = 7 + \frac{1}{4} = \frac{28}{4} + \frac{1}{4} = \frac{29}{4}$ hours Thursday: $3 \frac{3}{4} = 3 + \frac{3}{4} = \frac{12}{4} + \frac{3}{4} = \frac{15}{4}$ hours 3. **Find a common denominator to add all fractions:** The denominators are 2 and 4. The least common denominator is 4. Convert fractions with denominator 2 to denominator 4: $\frac{11}{2} = \frac{11 \times 2}{2 \times 2} = \frac{22}{4}$ $\frac{9}{2} = \frac{9 \times 2}{2 \times 2} = \frac{18}{4}$ 4. **Add all hours:** $$\frac{22}{4} + \frac{18}{4} + \frac{29}{4} + \frac{15}{4} = \frac{22 + 18 + 29 + 15}{4} = \frac{84}{4}$$ 5. **Simplify the total hours:** $$\frac{84}{4} = \frac{\cancel{84}^{21} \times 4}{\cancel{4}^1 \times 4} = 21$$ So, total hours worked = 21 hours. 6. **Find the fraction of overtime hours to total hours:** Overtime hours = 3 Fraction = $\frac{3}{21}$ 7. **Simplify the fraction:** $$\frac{3}{21} = \frac{\cancel{3}^1}{\cancel{21}^7} = \frac{1}{7}$$ **Final answers:** - Total hours worked = 21 hours - Fraction of overtime hours = $\frac{1}{7}$