What are the differences between internal and external sources of recruitment ?

Explain any two external sources of recruitment .

Different between internal and external fertilization

Give one advantage of external sources of recruitment.

The ratio between the male and female existing employees in an organisation is 9 : 7. The ratio between the male and female in a new recruitment of 360 employees is 4 : 5. The new ratio between male and female employees after recruitment becomes 61 : 55. Find the difference between the male and female employees before recruitment?