"Yeah, Leo; thanks." McLeod pushed his quarter across the bar with one hand and scratched negligently at his beard with the fingers of the other. Nobody questioned him in this neighborhood. The beard, which had taken two months to grow, disguised his face, and he had given his name as McCaffery, allowing his landlord and others who heard it to make the natural assumption that he was of Irish descent.
He was waiting. He had been forced to move from his apartment; nobody wanted that dirty so-and-so, Professor McLeod, around. Besides, his money was running short. He had never seen the two thousand. "You'll get that when the Galactic bank cashes your royalty check," he had been told. He was waiting.
Not hiding. No. That wasn't possible. The U.B.I. could find him easily when they wanted him. There was no place he could have hidden from them for very long. A man needs friends to stay hidden from an efficient police organization for very long, and John Hamish McLeod had no friends. "Jack McCaffery" had, since he was a pleasant kind of fellow who made friends easily when he wanted them. But he had no illusions about his new friends. Let them once suspect, however faintly, that Good Old Jack McCaffery was really that Professor McLeod, and the game would be up.
The U.B.I. would find him again all right, whenever it wanted him. And McLeod hoped it would be soon because he was down to his last hundred bucks.
So he waited and thought about fifty thousand Galactic credits.
The mathematics was simple, but it conveyed an awful lot of information. To make fifty thousand credits from one thousandth of one percent royalties on a book selling at five credits the copy, one must needs sell a billion copies. Nothing to it.
5X·10-5 = 5·104
Ergo: X = 109
McLeod drew the equations on the bar with the tip of a wet forefinger, then rubbed them out quickly.
A billion copies in the first year. He should have seen it. He should have understood.
How many planets were there in the galaxy?