Two reason Andrew Carnegie was a "big deal" in business, was first in the way he took full advantage of vertical integration. Buying everything he needed, including railways, to run his business. He is best remembered for this method, another factor that contributed to his "big deal" is his strong-rooted belief in philanthropy. He donated roughly 90% of his wealth to charity. Going so far as to write "The Gospel of Wealth."
The chance of having a boy every the previous time are 1/2 each, and since there were three boys, you need to solve for 1/2*3, which gives you 1.8. I hope this helps.
