Question

MEDAL!


Two cards are selected from a deck of ten card from 1-10. Once a card is selected, it is not replaced. What is the probability that the first card selected is less than 5 and the second card is 5 or more?

Answer 1

@jim_thompson5910

Answer 2

http://www.algebra.com/algebra/homework/Probability-and-statistics.faq?hide_answers=1&beginning=6840

Answer 3

@SolomonZelman

Answer 4

Can you help me with another question, if you can?

Answer 5

So your deck is as follows:
`1` , `2` , `3` , `4` , `5` , `6` , `7` , `8` , `9` , `10`

\(\scriptsize\color{ slate }{\scriptsize{\bbox[5pt, royalblue ,border:2px solid royalblue ]{~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ }}}\)

When dealing with dependent events you multiply the 2 events.
And in your case, the probability of the second event is impacted by the outcome in the first event.

Now, the question is:
P(the first card selected is less than 5)

there are 10 cards altogether, and less than 5 is only 4 out of these 10.

Answer 6

why you a genius? O_O @SolomonZelman

Answer 7

\[\frac{ 4 }{ 10 } \times \frac{ 6 }{ 9 }\]

Answer 8

Is that correct? Jim Thompson showed that to me.

Answer 9

so after you selected the first card less than 5, you have only 9 cards left.
which 3 of them are less than 5 (since 1 card less than 5 you already used up- remember, no replacement)

So, 6 out of 9 are less than 5.

Good, your answer expression is correct.

Answer 10

Okay thank you.. Can you help me with another question?

Answer 11

@nono266 , not at all -:(
@calculusxy , I will try my best.

Answer 12

thanks. Should i make a new post?

Answer 13

pls @SolomonZelman

Answer 14

was submitting another messages took long, excuse me.
According to the policy you should, not that I would insist.

I don't care about medals. Or at least stopped doing that after 5k

Answer 15

tnx for the complement, nono:)

Answer 16

alright, will see you if I get to your question