A Tangled Tale Lewis Carroll (books for 20 year olds TXT) 📖

“5,” but, as no working is given with it, it must, in accordance with the rule, remain “a deed without a name.” Janet makes it “35 and ²⁄₁₀ths.” I am sorry she has misunderstood the question, and has supposed that those who had lost an ear were 75 percent of those who had lost an eye; and so on. Of course, on this supposition, the percentages must all be multiplied together. This she has done correctly, but I can give her no honours, as I do not think the question will fairly bear her interpretation, Three Score and Ten makes it “19 and ²⁄₈ths.” Her solution has given me⁠—I will not say “many anxious days and sleepless nights,” for I wish to be strictly truthful, but⁠—some trouble in making any sense at all of it. She makes the number of “pensioners wounded once” to be 310 (“percent,” I suppose!): dividing by 4, she gets 77 and a half as “average percentage:” again dividing by 4, she gets 19 and ²⁄₈ths as “percentage wounded four times.” Does she suppose wounds of different kinds to “absorb” each other, so to speak? Then, no doubt, the data are equivalent to 77 pensioners with one wound each, and a half-pensioner with a half-wound. And does she then suppose these concentrated wounds to be transferable, so that ²⁄₄ths of these unfortunates can obtain perfect health by handing over their wounds to the remaining ¼th? Granting these suppositions, her answer is right; or rather, if the question had been “A road is covered with one inch of gravel, along 77 and a half percent of it. How much of it could be covered 4 inches deep with the same material?” her answer would have been right. But alas, that wasn’t the question! Delta makes some most amazing assumptions: “let every one who has not lost an eye have lost an ear,” “let every one who has not lost both eyes and ears have lost an arm.” Her ideas of a battlefield are grim indeed. Fancy a warrior who would continue fighting after losing both eyes, both ears, and both arms! This is a case which she (or “it?”) evidently considers possible.

Next come eight writers who have made the unwarrantable assumption that, because 70 percent have lost an eye, therefore 30 percent have not lost one, so that they have both eyes. This is illogical. If you give me a bag containing 100 sovereigns, and if in an hour I come to you (my face not beaming with gratitude nearly so much as when I received the bag) to say “I am sorry to tell you that 70 of these sovereigns are bad,” do I thereby guarantee the other 30 to be good? Perhaps I have not tested them yet. The sides of this illogical octagon are as follows, in alphabetical order:⁠—Algernon Bray, Dinah Mite, G. S. C., Jane E., J. D. W., Magpie (who makes the delightful remark “therefore 90 percent have two of something,” recalling to one’s memory that fortunate monarch, with whom Xerxes was so much pleased that “he gave him ten of everything!”), S. S. G., and Tokyo.

Bradshaw of the Future and T. R. do the question in a piecemeal fashion⁠—on the principle that the 70 percent and the 75 percent, though commenced at opposite ends of the 100, must overlap by at least 45 percent; and so on. This is quite correct working, but not, I think, quite the best way of doing it.

The other five competitors will, I hope, feel themselves sufficiently glorified by being placed in the first class, without my composing a Triumphal Ode for each!

Class List.

Old Cat.

Old Hen.

Polar Star.

Simple Susan.

White Sugar.

Bradshaw of the Future.

T. R.

Algernon Bray.

Dinah Mite.

G. S. C.

Jane E.

J. D. W.

Magpie.

S. S. G.

Tokyo.

§2: Change of Day

I must postpone, sine die, the geographical problem⁠—partly because I have not yet received the statistics I am hoping for, and partly because I am myself so entirely puzzled by it; and when an examiner is himself dimly hovering between a second class and a third how is he to decide the position of others?

§3: The Sons’ Ages

Problem.⁠—“At first, two of the ages are together equal to the third. A few years afterwards, two of them are together double of the third. When the number of years since the first occasion is two-thirds of the sum of the ages on that occasion, one age is 21. What are the other two?”

Answer.⁠—“15 and 18.”

Solution.⁠—Let the ages at first be x, y, (x+y). Now, if a+b=2c, then (a−n)+(b−n)=2(c−n), whatever be the value of n. Hence the second relationship, if ever true, was always true. Hence it was true at first. But it cannot be true that x and y are together double of (x+y). Hence it must be true of (x+y), together with x or y; and it does not matter which we take. We assume, then, (x+y)+x=2y; i.e. y=2x. Hence the three ages were, at first, x, 2x, 3x; and the number of years, since that time is two-thirds of 6x, i.e. is 4x. Hence the present ages are 5x, 6x, 7x. The ages are clearly integers, since this is only “the year when one of my sons comes of age.” Hence 7x=21, x=3, and the other ages are 15, 18.

Eighteen answers have been received. One of the writers merely asserts that the first occasion was 12 years ago, that the ages were then 9, 6, and 3; and that on the second occasion they were 14, 11, and 8! As