Question

Ella has twelve cards numbered I to 12. What is the probability she picks three even-numbered cards in a row, if the first two cards are not replaced?

Answer 1

1/11

Explanation:

even #s between (or including) 1 and 12:

2, 4, 6, 8, 10, 12

there are 6

6/12 for the first one

5/11 for the second one (one even # less)

4/10 for the third one

To find the probability of picking three even numbers from 1 to 12 in a row three times:

multiply the probabilities together:

(6/12)*(5/11)*(4/10)=(24/120)*(5/11)=(12/60)*(5/11)=(1/5)*(5/11)=5/55=1/11