A CARD IS DRAWN FROM A PACK OF 52 CARDS AND A GAMBLER BETS THAT IT IS A SPADE OR AN ACE . WHAT ARE THE ODDS AGAINST HIS WINNING THIS BET?

PLEASE TELL THAT WHAT IS THE SENSE OF THE LAST STATEMENT OF THIS QUESTION?

the odds against winning is $\frac{probability of lo\sin g}{probability of winning}$
the number of spade cards = 13
number of ace cards = 4 [including one spade card]
number of spade or ace cards = 13+4-1=16
the probability of getting spade or ace card, i.e. probability of winning = $\frac{16}{52}=\frac{4}{13}$
the probability of losing = $1-\frac{4}{13}=\frac{13-4}{13}=\frac{9}{13}$
therefore odds against winning $=\frac{9/13}{4/13}=\frac{9}{4}$
thus odd against his winning is 9:4

hope this helps you