21 JULY 1877, Page 14

SAFE BETTING.

(TO THE EDITOR OP THE " SPECTATOR:1

SIII,—Tho mathematical principle of "Safe Betting" is con- tained in a question propounded at Cambridge in the Senate- House problems for January 8, 1839, and is merely a matter of the solution of a simple equation. Here is the question :—" The odds against m horses are n, to 1, n2 to 1, n, to 1 to 1. Show that, except in the particular case in which the sum of the reciprocals of 7/1+ 1, v2+ 2 &c., is unity, a person may so arrange his bets as to win a given sum, whichever horse be suc- cessful; and that he must bet against or back every horse, ac- cording as the above sum is greater or less than unity." The " exceptional " case is, of course, when the betting is, as "X. Y."

says, "scientifically correct."—I am, Sir, &c., A.