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23 Apr 2026, 22:06
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In a certain baord game, a stack of 48 cards, 8 of which : Problem Solving (PS)
why does the below approach doesn't work here. I applied exactly this - 8/48 and the answer should've been 1/6 but it's not. What's the difference between these two.
Please brief me, i don't want to make similar mistakes going forward Bunuel
Thanks in advance,
Swetha
why does the below approach doesn't work here. I applied exactly this - 8/48 and the answer should've been 1/6 but it's not. What's the difference between these two.
Please brief me, i don't want to make similar mistakes going forward Bunuel
Thanks in advance,
Swetha
Bunuel
23 Apr 2026, 22:23
Kudos
Bookmarks
SwethaReddyL
The difference is that in the black ball example, you are not given any information about the earlier draws, so the probability that a specific draw is black stays the same as the initial proportion.
In the cars example, you are told that the first 2 cards are not stock cards. That extra information changes the composition of the remaining stack, so now there are still 8 stock cards but only 46 cards left. So this is a conditional probability question, not the unconditional “any position is equally likely” idea.
In fact, if the question had simply asked for the probability that the third card is a stock card, without telling you anything about the first 2 cards, then 8/48 = 1/6 would be correct.
