Answer 1

Total number of female students = 300 - 142
\[ = 158\]
Total number of female teachers = 30 - 12
\[ = 18\]
Total number of females = 158 + 18
\[ = 176\]
Total population of the school = 300 + 30
\[ = 330\]
Percentage of females \[= \frac{176}{330} \times 100\]
\[ = \frac{160}{3} \%\text{ or }53 . 33\%\]