MHB [ASK] Probability of Getting the Main Doorprize

  • Thread starter Thread starter Monoxdifly
  • Start date Start date
  • Tags Tags
    Probability
Monoxdifly
MHB
Messages
288
Reaction score
0
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?
 
Mathematics news on Phys.org
Hi Mr. Fly!

I'm assuming those 30 doorprizes are divided randomly among the 240 members.
And that the 15 tickets in Mr. Aziz's family correspond to 15 members.
And that there is only 1 main doorprize.
Just checking, is it a typo that you write 'the main ones' as plural?
Otherwise it suggests that there is more than 1 main doorprize.

If there is only 1 main prize, and Mr. Aziz has 15 chances out of 240 on it, then the probability that Mr. Aziz gets the main doorprize is 15/240 = 1/16.

Note that if my interpretation is correct, we can expect that Mr. Aziz's family collects $\frac{15}{240 }\cdot 30$ door prizes as opposed to the 15/240 that you suggested.
Since only 1 of them is the main prize, we multiply indeed by 1/30, resulting in the $\frac{15}{240}\cdot 30\cdot \frac{1}{30}=\frac{15}{240}=\frac{1}{16}$ that I already mentioned.
 
Last edited:
I see no reason to even consider the "30 door prizes". The question is only about the one main prize. There are 240 people and 15 of them are in this family. The probability of someone in this family winning the one main prize is \frac{15}{240}= \frac{1}{16}.
 
Thank you, both of you. And yes, Klaas, that was a typo.
It has been quite a long time since someone calls me Mr. Fly...
 
Insights auto threads is broken atm, so I'm manually creating these for new Insight articles. In Dirac’s Principles of Quantum Mechanics published in 1930 he introduced a “convenient notation” he referred to as a “delta function” which he treated as a continuum analog to the discrete Kronecker delta. The Kronecker delta is simply the indexed components of the identity operator in matrix algebra Source: https://www.physicsforums.com/insights/what-exactly-is-diracs-delta-function/ by...
Fermat's Last Theorem has long been one of the most famous mathematical problems, and is now one of the most famous theorems. It simply states that the equation $$ a^n+b^n=c^n $$ has no solutions with positive integers if ##n>2.## It was named after Pierre de Fermat (1607-1665). The problem itself stems from the book Arithmetica by Diophantus of Alexandria. It gained popularity because Fermat noted in his copy "Cubum autem in duos cubos, aut quadratoquadratum in duos quadratoquadratos, et...
I'm interested to know whether the equation $$1 = 2 - \frac{1}{2 - \frac{1}{2 - \cdots}}$$ is true or not. It can be shown easily that if the continued fraction converges, it cannot converge to anything else than 1. It seems that if the continued fraction converges, the convergence is very slow. The apparent slowness of the convergence makes it difficult to estimate the presence of true convergence numerically. At the moment I don't know whether this converges or not.
Back
Top