Question 1105388
Use 1000.
=====B===========G========total
<21--- 440----------360========800
>21----160------------40========200
Total--600-----------400---------1000

a. <21 is 0.45 probability of being a girl.
b. 0.44 probability of being a boy under 21
c. Boy less than 21 is 0.73 probability, given that a boy is chosen.