#### An office opens at 9 a.m. and closes at 5.30 p.m. with a lunch break of 30 minutes. What is the ratio of lunch break to the total period in the office?

Given: Office opening time = 9 a.m.
Office closing time = 5.30 pm
Time duration in office = 8 hours 30 minutes = 510 minutes
lunch break =30 minutes
Ratio of lunch break to the total period in the office $\\ \frac{\text { lunch break }}{\text { Time duration in office }} =\frac{30 \text { minutes }}{510 \text { minutes }}=\frac{1}{17}=1: 17$