390.--THE HORSE-RACE PUZZLE.

There are no morals in puzzles. When we are solving the old puzzle of

the captain who, having to throw half his crew overboard in a storm,

arranged to draw lots, but so placed the men that only the Turks were

sacrificed, and all the Christians left on board, we do not stop to

discuss the questionable morality of the proceeding. And when we are

dealing with a measuring problem, in which certain thirsty pilgrims are

to make an equitable division of a barrel of beer, we do not object

that, as total abstainers, it is against our conscience to have anything

to do with intoxicating liquor. Therefore I make no apology for

introducing a puzzle that deals with betting.

Three horses--Acorn, Bluebottle, and Capsule--start in a race. The odds

are 4 to 1, Acorn; 3 to 1, Bluebottle; 2 to 1, Capsule. Now, how much

must I invest on each horse in order to win £13, no matter which horse

comes in first? Supposing, as an example, that I betted £5 on each

horse. Then, if Acorn won, I should receive £20 (four times £5), and

have to pay £5 each for the other two horses; thereby winning £10. But

it will be found that if Bluebottle was first I should only win £5, and

if Capsule won I should gain nothing and lose nothing. This will make

the question perfectly clear to the novice, who, like myself, is not

interested in the calling of the fraternity who profess to be engaged in

the noble task of "improving the breed of horses."

Amusements in Mathematics · 第 454 / 970 题