"We have agreed, to begin with, that the population of Philadelphia is one hundred and of New York one hundred and fifty. Now, how many people will have to be subtracted from New York's population to make it the same as Philadelphia?"
"Feefty,—vot I says."
"And fifty is what part of one hundred and fifty,—that is, what part of the population of New York?"
"It vos one thirds."
"And one third of anything is thirty-three and one third per cent. of it, which is the correct answer to the problem."
Mr. Ribsam held his pipe suspended in one hand while he stared with open mouth into the smiling face of his son, as though he did not quite grasp his reasoning.
"Vot you don't laughs at?" he said, turning sharply toward his wife, who had resumed her knitting and was dropping many a stitch because of the mirth, which shook her as vigorously as it stirred her husband a few minutes before.
"I laughs ven some folks dinks dey ain't shmarter don dey vosn't all te vile, don't it?"
And stopping her knitting she threw back her head and laughed unrestrainedly. Her husband hastily shoved the stem of his pipe between his lips, sunk lower down in the chair, and smoked so hard that his head soon became almost invisible in the vapor.
By-and-by he roused himself and asked Nick to begin with the first problem and reason out the result he obtained with each one in turn.