Solution:Let the total number of employees in the firm = 100
Number of male employees = 70
Number of female employees = 30
30% of male employees opt for voluntary retirement = 30/100 × 70 = 21
20% of female employees opt for voluntary retirement
= 20/100 × 30 = 6
Now, total number of male and female employees continue in service
= (70 - 21) + (30 - 6) = 49 + 24 = 73 %