Abox contains 20 cards numbered 1–20. you select a card. without replacing the first card, you select a second card. find p(1, then 20).

1/380

Step-by-step explanation:

Probability is the likelihood or chance that an event will occur.

Probability = expected outcome of event/Total outcome.

Since the box contains 20 cards, the total outcome is 20.

If a card is first selected from the total card, the probability of selecting the card will be 1/20.

Since the card isn't replaced after selecting, the total card remaining will be 19, which will be our new total outcome.

If the second card is selected, the probability of selecting the second card will be 1/19.

Probability of selecting the first and then the second will give:

1/20×1/19

= 1/380

i think it would be 42cm