All outcomes of three children (using G for girl and B for boy)
GGG, GGB,GBG,GBB,BGG,BGB,BBG,BBB
1) exactly two is 3 out of 8 total outcomes, or 3/8
2) all sons is one outcome, or 1/8
The possibility is 3 : 1/2 * 6/1 = 3/1
Answer:
1/128 * (3 - 4cos2x + cos4x)
Step-by-step explanation:
See attachment for steps