A card is drawn at random from an ordinary deck of

playing cards. Find the following odds:
Odds against drawing a king, queen, jack, or ace

Would this not be 16/52=4/13

I would call 4/13 the probability of drawing one of those cards.

The odds against the cards being drawn is 9:4. That is the probability ratio of (not happening) to (happening).

To find the odds against drawing a king, queen, jack, or ace from an ordinary deck of playing cards, we first need to determine the number of cards that are not kings, queens, jacks, or aces.

In a standard deck of playing cards, there are 4 kings, 4 queens, 4 jacks, and 4 aces, making a total of 16 cards that are kings, queens, jacks, or aces.

The deck contains a total of 52 cards, so the remainder (52 - 16 = 36) are cards that are not kings, queens, jacks, or aces.

The odds against drawing a king, queen, jack, or ace can be expressed as the ratio of the number of unfavorable outcomes to the number of favorable outcomes.

In this case, the number of unfavorable outcomes (cards that are not kings, queens, jacks, or aces) is 36, and the number of favorable outcomes (kings, queens, jacks, and aces) is 16.

Therefore, the odds against drawing a king, queen, jack, or ace from an ordinary deck of playing cards are 36/16, or simplified, 9/4.