Are you smarter than an 8th grader?

Reply #21

Speler — Sat, 12 Feb 2022 23:14:01 GMT

(0.5*1/8)+0.5

=0.5625

(0.5*1/8)/0.5625

=0.1111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111

0.5625/(0.5*1/8)

=9

Reply #20

Speler — Sat, 12 Feb 2022 23:09:12 GMT

The probability of picking the fair coin is 0.5.

Reply #19

Speler — Sat, 12 Feb 2022 23:05:25 GMT

I heard that one in class, but don't think that it is written in my course. Same for the calculation of PI and alike.

Reply #18

CARBOB — Wed, 19 Jan 2022 14:04:41 GMT

Very good, always give examples! Helps to clarify

Reply #17

cottoneyedjoe — Mon, 17 Jan 2022 04:24:06 GMT

This is almost correct except you have to use the probability of getting three heads on three flips with a fair coin, not the overall probability of getting heads on any flip. So you get 0.5 x 0.5 x 0.5 = 0.125 = 1/8 as the probability of three heads in three flips of the fair coin. (The part about flipping it three times isn't extraneous information in the statement of the problem.

Reply #16

Soledad — Mon, 17 Jan 2022 03:12:54 GMT

Ok, half of the time it is expected you pick the fair coin and half of the time the trick coin, hence 50/50. When you pick the fair coin, half of the times you get heads. When you pick the trick coin all of the time you get heads. Out of the 4 chances of getting heads, 2 sides to each coin, 3 out of 4 you will get heads. So out of 100 chances, 25 chances it was the fair coin, and 50 chances it was the trick coin. So 1/3 I would say.

Reply #15

Soledad — Mon, 17 Jan 2022 03:08:37 GMT

Ok gimme a sec. I'm gonna reply to grwurston, and then maybe you can reply to me. You have me a little confused with your 1/8

Reply #14

Soledad — Mon, 17 Jan 2022 02:58:57 GMT

Lol yooooo

Reply #13

rdgrnr — Mon, 17 Jan 2022 01:04:54 GMT

Oh, I could tell you stories about them that would make your head spin right the hell off.

But I'm not one to talk.

So don't get me started.

Reply #12

cottoneyedjoe — Mon, 17 Jan 2022 00:50:22 GMT

I suppose he could let one rip really loud. You probably have some good ex-inlaw stories about that.

Reply #11

rdgrnr — Mon, 17 Jan 2022 00:20:32 GMT

Why does the guy flipping the coins have to shout?

I would find that very annoying.

It's like I was telling a friend of mine the other day when he asked if the reason I didn't like to fly was because I was afraid of the plane crashing. I told him no, I wasn't afraid of the plane going down but what I didn't like was the prospect of all the people on the plane screaming OH NO! WE'RE ALL GONNA DIE! That would give me a really bad headache.

Reply #10

Wentworth — Sun, 16 Jan 2022 17:58:24 GMT

Whatever you guys are smokin or sniffin...probablymodel airplane glue you aren't eight graders

anymore...leave that stuff alone....

Reply #9

cottoneyedjoe — Sun, 16 Jan 2022 17:49:34 GMT

The answer is 1/9.

Think of it like this. Pretend your friend is in another room of the house and he's playing with the two coins. He follows this procedure: shuffle the coins in his hand, choose one randomly, flip it three times. If he gets three heads he shouts out, Hey I got three heads! and repeats the procedure (shuffling the coins, randomly choosing one, flipping it three times.) If he gets any sequence other than three heads, he stays quiet and repeats the procedure. Pretend he does th... [ More ]

Reply #8

grwurston — Sun, 16 Jan 2022 08:21:12 GMT

So then what is it

Reply #7

Soledad — Sun, 16 Jan 2022 02:30:30 GMT

No. That's the initial thought. Everybody thinks that at first. But that's not it. That's not the oh

Reply #6

grwurston — Sun, 16 Jan 2022 01:47:08 GMT

It's either one or the other. 1 out of 2, 50-50...

Reply #5

Soledad — Sun, 16 Jan 2022 01:17:06 GMT

Lol is it silver. What percentage of silver, go see the metalsmith. Is it 800 European silver or 925 sterling, haha.

I think it doesn't matter how many times you flip it, the odds are the same, but the relevance is with the fact of how many times you actually did say. So, oh I am smarter than a 8th grader. Thank you. Like the question. Bayes answers it 12...3. Or 21...3. Haha

Reply #4

cottoneyedjoe — Sat, 15 Jan 2022 23:36:17 GMT

Doesn't matter what it's made of. You could assume it's wood and the heads and tails are painted with expensive lacquer.

It's a question from an old middle school mathletes competition. If you can't work out the right answer, I guess you're not smarter than a smart 8th grader.

Reply #3

Speler — Sat, 15 Jan 2022 18:25:13 GMT

Let's say that Kennedy is on both sides of a half-dollar silver coin. Who killed Kennedy

Reply #2

JeetKuneDoLotto — Sat, 15 Jan 2022 18:03:29 GMT

What is the chemical composition of the coin?

Gold?

Silver?

Ceramic?

Graphene Oxide

Reply #1

Speler — Sat, 15 Jan 2022 17:32:42 GMT

For which coin

Are you smarter than an 8th grader?

cottoneyedjoe — Fri, 14 Jan 2022 01:12:56 GMT

Middle school math competition question:

You have two coins: one fair, and one that is heads on both sides. You randomly choose one of the coins without looking at it and flip it three times in a row. It comes out heads each time. (Assume you don't look at the coin except when it lands and have no other information). What is the probability it's the fair coin