Determine the probability of the following:

Question

1.Determine the probability of the following:

b) not getting a face card when one card is pulled from a deck. Is it 40/51?

c) having a test on a Thursday, isn't this subjective probability?

Answer 1

Face cards are K,Q and J, 3 out 13 cards in each of the 4 suits. that's probability of 3/13 of getting a face card. Subtract that from 1

1-3/13 = 13/13 -3/13 = 10/13

10/13 = 40/52

There are 3x4= 12 face cards. 12/52 = odds of getting a face card

subtract that from 1

1-12/52 = 52/52 - 12/52 = 40/52 = probability of not getting a face card

= about 77% chance of not getting a face card

Unless you meant one card has been removed from the deck before drawing a card

then your deck now has 51 cards. but the card that was first removed from the deck already had odds of 40/52 of not being a face card. The odds don't change on drawing a card from the now 51 cards remaining. Odds are (10/13)(51)/51

=10/13 =40/52

Unless you meant the first card removed was a face card, leaving odds of a non-face card on the next draw to be 40/51

Having a test on Thursday is 20% if classes are 5 days a week.

It's more objective if you have historical data, such as if there has never been a test given on a Thursday, then odds are low it will happen. If every test ever given was on a Thursday, odds are very high another test will be on a Thursday.

You could also check to see if holidays are falling on a Thursday, such as Thanksgiving. Then odds are less than 20%. But if more holidays are on Mondays and Fridays, then maybe Thursdays are higher than 20%