Hey there! Sign in to join this conversationNew here? Join for free
x Turn on thread page Beta
    • Thread Starter
    Offline

    7
    ReputationRep:
    Hey I have a problem. The question which i cannot do is this:
    A player chooses a card at random from each of 3 packs of cards.
    Calculate the probability he draws an image card (king, queen or jack)
    I have no idea how to even begin this question
    Offline

    14
    ReputationRep:
    well theres 52 cards in a pack and 12 face cards...

    so 12/52 ?
    Offline

    12
    ReputationRep:
    i;ve seen you make a good few questions for probability and related questions in the past couple of days.

    try and think a bit harder. what are the probabilities?

    ask yourself things like:
    how many cards are there in a pack?
    how many kings, queens and jacks are there in total in each pack?
    so what is the probability of picking a jack/queen/king (picture card) from the pack?
    what about the same questions but for 3 packs, if a player draws one, at random, from each?
    Offline

    14
    ReputationRep:
    oops misread the question :P

    but surely then just multiply by 3?
    Offline

    1
    ReputationRep:
    Start by considering one pack of cards, there's usually 52 in these sorts of questions.
    there are four suits, and 3 image cards in each suit. Consider the probability here.
    then, multiply this by 3 as you have 3 packs.
    Offline

    12
    ReputationRep:
    are you sure? the question merely states, what is the chance of drawing a picture card, not specifically one. so all 3 could be picture cards, or just two, or just one...

    Spoiler:
    Show
    the way i would do it is to say that:
    P(X \geq 1) = 1-P(X=0)
    • Thread Starter
    Offline

    7
    ReputationRep:
    (Original post by Higgy90)
    well theres 52 cards in a pack and 12 face cards...

    so 12/52 ?
    sorry i didnt write up the whole question calculate the probability that he draws 1 image card, 2 image card and 3 image cards
    Offline

    12
    ReputationRep:
    Assume that there is an equal probability of choosing the cards. You are picking 3 cards from 156, 36 of which are image cards. The probability of having at least one image card in your chosen cards is 1 minus the probability of picking no image cards (these events partition the sample space).
    The number of ways of picking 3 non image cards is (120x119x118)/6.
    The number of ways of picking 3 cards from 156 is (156x155x154)/6
    Therefore, the probability drawing an image card is

    1 - (120x119x118)/(156x155x154)
 
 
 
Reply
Submit reply
Turn on thread page Beta
Updated: November 11, 2008
Poll
Do you agree with the proposed ban on plastic straws and cotton buds?
Useful resources

Make your revision easier

Maths

Maths Forum posting guidelines

Not sure where to post? Read the updated guidelines here

Equations

How to use LaTex

Writing equations the easy way

Student revising

Study habits of A* students

Top tips from students who have already aced their exams

Study Planner

Create your own Study Planner

Never miss a deadline again

Polling station sign

Thinking about a maths degree?

Chat with other maths applicants

Can you help? Study help unanswered threads

Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.