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put this solution on YOUR website!Look at the possible outcomes of the children in order of birth.
There are

or

total outcomes.
1.B B B B
2.B B B G
3.B B G B
4.B B G G
5.B G B B
6.B G B G
7.B G G B
8.B G G G
9.G B B B
10.G B B G
11.G B G B
12.G B G G
13.G G B B
14.G G B G
15.G G G B
16.G G G G
Look at the outcomes that have two boys and two girls.
There are 6 of them (4,6,7,10,11,13).