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Forum » math question for reps
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Thread: math question for reps

post 1663427813 06-25-2022, 10:20 AM
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math question for reps

Suppose a jar contains 17 red marbles and 15 blue marbles. If you reach in the jar and pull out 2 marbles at random at the same time, find the probability that both are red.
There is no they…
post 1663427823 06-25-2022, 10:20 AM
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Bout 350%
Sloots Gon Sloot.
post 1663428533 06-25-2022, 10:35 AM
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27,42%
post 1663428793 06-25-2022, 10:41 AM
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Originally Posted By MiscMathematician⏩
17/32*16/31
This..

Op, what is this for?
post 1663429223 06-25-2022, 10:52 AM
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Originally Posted By MiscMathematician⏩
17/32*16/31
this is correct

reasoning:

when you're finding the probability that something is happening at the same time (together), you multiply the probability together

probability that you pull out a red marble the first time is 17/32

probability that you pull out a red marble again AFTER pulling a red marble the first time is 16/31

it goes from 17/32 to 16/31 because you're accounting for the first red marble being pulled

multiplying two events happening together 17/32x16/31

when you want to find the probability of two or more events not happening together you add them
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post 1663429303 06-25-2022, 10:54 AM
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How big is the jar?
post 1663448603 06-25-2022, 06:17 PM
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Originally Posted By MiscMathematician⏩
17/32*16/31
Nice bro, can you help me out with some graphing linear equations? I wish I could just "get" math.
Originally Posted By headturner1⏩
This..

Op, what is this for?
psy degree but have to take a couple math classes, and I literally am dyslexic with numbers.
Originally Posted By xbluexhawkx⏩
this is correct

reasoning:

when you're finding the probability that something is happening at the same time (together), you multiply the probability together

probability that you pull out a red marble the first time is 17/32

probability that you pull out a red marble again AFTER pulling a red marble the first time is 16/31

it goes from 17/32 to 16/31 because you're accounting for the first red marble being pulled

multiplying two events happening together 17/32x16/31

when you want to find the probability of two or more events not happening together you add them
nice, preesh the explanation.
There is no they…
post 1663448803 06-25-2022, 06:22 PM
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17/32 = 0.53125

16/31 = 0.516129

0.53125 * 0.516129 = 0.27419

So I get 27.41% chance for it to be two reds in a row given the numbers.
post 1663450003 06-25-2022, 06:53 PM
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A jar that contains exactly 17 red marbles, 15 blue marbles, and 6 green marblesdoescontain 17 red marbles and 15 blue marbles, fitting the OP given info, in which case the answer is ambiguous. Taking the common interpretation of exactly 32 marbles, 17 of which are red, and 15 of which are blue.....

Edit: wizarded by above, didnt see MiscMath's second post
Probability = # of successes / # of possibilities

# of success = number of possible combinations of 2 reds (picture if each red marble was numbered..how many pairs of reds) = 17 choose 2.

# of possibilities = number of possible combinations of 2 marbles = 32 choose 2.

Probability of 2 reds = (17 choose 2) / (32 choose 2) = (17! / 2!*15!) / (32! / 30!* 2!) = 17*16/(32*31) = 17/62, as MiscMathematician says above. Note probability is a decimal between 0 and 1, and not a percentage.
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post 1663451263 06-25-2022, 07:31 PM
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Originally Posted By LtGoose⏩
How big is the jar?
Not as big as the regret your parents have over your failed abortion.
There is no they…
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