Math Is Fun Forum

Monox D. I-Fly

Member

From: Indonesia

Registered: 2015-12-02

Posts: 2,000

[ASK] Probability of Getting the Main Doorprize

There's an event which is joined by 240 members. The Event Organizer prepares 30 doorprize with one of them being the main ones. If Mr. Aziz's family has 15 tickets, the probability that Mr. Aziz gets the main doorprize is ....
A. 1/16
B. 1/8
C. 1/4
D. 1/2

I thought the answer was 15/240 (the probability of Mr. Aziz's family getting the doorprize) times 1/30 (the main one among the doorprize) and it results in 1/480, but it's not in the options. Is the book wrong or am I the one who miscalculated?

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Actually I never watch Star Wars and not interested in it anyway, but I choose a Yoda card as my avatar in honor of our great friend bobbym who has passed away.
May his adventurous soul rest in peace at heaven.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,140

Re: [ASK] Probability of Getting the Main Doorprize

hi Monox D. I-Fly

As the 'event' is the main prize I don't think it matters about any other prizes.  We should have been told that 240 tickets have been allocated.  This is not a trivial point as one member controls 15 tickets.  Is it allowed for one person to have more than one ticket or must we assume that Mr Aziz has 15 in his family and they are all members?

But we don't know all this so I'll assume that 240 tickets have been given out and he has 15 of them   One ticket will get the main prize, so he has 15/240 chances of getting it.

Bob

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Monox D. I-Fly

Member

From: Indonesia

Registered: 2015-12-02

Posts: 2,000

Re: [ASK] Probability of Getting the Main Doorprize

Ah, thank you. Guess I was overthinking this.

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Actually I never watch Star Wars and not interested in it anyway, but I choose a Yoda card as my avatar in honor of our great friend bobbym who has passed away.
May his adventurous soul rest in peace at heaven.