just what I don't know?"

"I can't say what you don't know. This is something that _I_ know very
well."

"But you know everything," she murmured.

Without seeking to deny this, Queed said: "It tells you right there in
the book."

"I don't see it," said Fifi, nervously looking high and low, not only in
the book but all over the room.

The young man fell back on the inductive method: "What is that six
then?"

"Oh! _Now_ I see. It's the difference in the number of days
consumed--isn't it?"

"Naturally. Now put down your equation. No, no! The greater the rate of
progress, the fewer the number of days. Do not attempt to subtract the
greater from the less."

Now Fifi figured swimmingly:--

(105/(x-2)) - (105/x) = 6

105x - 105x + 210 = 6x^2 - 12x

6x^2 - 12x - 210 = 0

6x^2 - 12x - 210 = 0

x^2 - 2x - 35 = 0

(x - 7) (X + 5) = 0

x = 7 or -5

She smiled straight into his eyes, sweetly and fearlessly. "Seven! Just
what you said! Oh, if I could only do them like you! I'm ever and ever
so much obliged, Mr. Queed--and now I can go to bed."

Mr. Queed avoided Fifi's smile; he obviously deliberated.

"If you have any more of these terrible difficulties," he said slowly,
"it isn't necessary for you to sit there all evening and cry over them.
You ... may ask me to show you."

"Oh, _could_ I really! Thank you ever so much. But no, I won't be here,
you see. I didn't mean to come to-night--truly, Mr. Queed--I know I
bother you _so_--only Mother made me."

"Your mother made you? Why?"

"Well--it's right cold upstairs, you know," said Fifi, gathering up her
books, "and she thought it might not be very good for my cough...."

Queed glanced impatiently at the girl's delicate face. A frown deepened
on his brow; he cleared his throat with annoyance.

"Oh, I am willing," he said testily, "for you to bring your work here
whenever it is very cold upstairs."

"Oh, how good you are, Mr. Queed!" cried Fifi, staggered by his
nobility. "But of course I can't think of bothering--"

"I should not have asked you," he interrupted her, irritably, "if I had
not been willing for you to come."

But for all boarders, their comfort and convenience, Fifi had the great
respect which all of us feel for the source of our livelihood; and,
stammering grateful thanks, she again assured him that she could not
make such a nuisance of herself. However, of course Mr. Queed had his
way, as he always