J@ckrbs Random Riddles! (Revived!)

[Andrew]

101 x 5 = 505 = SOS, so apparently the roommate is in some sort of trouble.

[MegaMarbler]

101 x 5 = 505 (SOS)

EDIT: didn't realize there was another page. -_-

[J@ckrb]

Correct! The note reads SOS. What kind of trouble could he be in though?

Scores:
Andrew: 7 (+1)
Don.Gato: 6
MegaMarbler: 1

Puzzle 8 - What Day Is It? 1 - Easy

If yesterday's day after tomorrow is Sunday, what day is tomorrow's day before yesterday?

[Don.Gato]

Friday

[J@ckrb]

Correct!

Scores:
Andrew: 7
Don.Gato: 7 (+1)
MegaMarbler: 1

Puzzle 9 - Mathematchsticks - Medium

A maths equation is written using matchsticks. It reads:

I + XI = X, or 1 + 11 = 10

But that's not right, is it? To make this into a mathematically correct equation, what's the fewest number of matchsticks do you need to move?

[Don.Gato]

1


1-11 = -10

or

I - XI = -X

[Andrew]

You could also do

I + X = XI
or
1 + 10 = 11

[Don.Gato]

well yeah, that's probably what he had in mind but..... mine is cleverer. And besides this hypothetical matchstick equation would look better if the creator had broken a matchstick in half to make the +, thus making my solution only require the movement of 1/2 a matchstick .

[J@ckrb]

Hint: Try to look at the equation at different angles... literally.

[Andrew]

Oh, duh. If you turn it upside down you get

X = IX + I, or 10 = 9 + 1.

So the fewest matchsticks you can move is 0.

[J@ckrb]

Correct! The question is worded to seems like you need to move a matchstick, but you don't need to.

Scores:
Andrew: 9 (+2)
Don.Gato: 7
MegaMarbler: 1

Puzzle 10 - Train Station Conundrum - Hard

It takes 15 minutes to travel from Station A to Station B.
A -> B 15 minutes
It takes 5 minutes to travel from Station B to Station C.
B -> C 5 minutes
It takes 10 minutes to travel from Station C to Station D.
C -> D 10 minutes
However, it doesn't take 30 minutes for a train to travel from Station A to D. How long would it take, using the information above, and that the railway is a straight line with no branches, for a train to travel from Station A to D?

[J@ckrb]

24hr Hint

This is impossible, right?

Well it isn't, you just have to be flexible with your thinking.

[MegaMarbler]

The train has to slow down when going from A -> B and B -> C and from C -> D, but going from A -> D you don't have to slow down, saving at least a minute (?)

[Don.Gato]

Hmm I think I see whats going on here. The stations are not labeled in order.

Of course there are still 2 possible answers,

I will guess 10 minutes.

(but 20 is also a possibility)

[J@ckrb]

Don.Gato is on the right track (but 10mins is not the right answer)

Unnecessary hint: A is the first station and D is the last, but is B after A? In the alphabet, it is, but Station B does not have to be after A. Flexibility.

[MegaMarbler]

15 minutes.

A -> C = 5 minutes
C -> D = 10 minutes

[Don.Gato]

No that can't be it, because then stations B and D would be in the same place. EDIT: on further reflection your answer doesn't work on many levels including the one above.


I have to stick to my guns here and make my next guess 20

[MegaMarbler]

25?

[J@ckrb]

Don.Gato is correct.

A - C - B - D is the station order.

It takes 15 mins to go from A to B.

It takes 10 mins to go from C to D.

B to D, the last part, is 10 mins (time taken from B to D) - 5 mins (time taken from C to B).

Therefore, A - C is 10 mins, C - B is 5 mins and B - D is 5 mins.

10 + 5 + 5 = 20 mins.

Scores:
Don.Gato: 10 (+3)
Andrew: 9
MegaMarbler: 1

Puzzle 11 - What Day Is It? 2 - Easy

If seven days after 70 days ago is Sunday, seven days before 70 days ago is what day of the week?

[Andrew]

Sunday

[Don.Gato]

And my first guess of 10 worked out perfectly too....

stations in the order a-d-b-c
15 minutes to b + 5 to c - 10 to d = 10

[J@ckrb]

Andrew is correct! If the number of days are divisible by 7, it will always be the same day.

(NB: I screwed up a bit on the last puzzle, Don.Gato. I should of included that station A was the first stop and that D was the last stop, making 20 minutes the only correct answer)

Scores:
Don.Gato: 10
Andrew: 10 (+1)
MegaMarbler: 1

Puzzle 12 - A Stacked Deck - Medium

There are 52 cards - 26 red and 26 black, and no jokers - in this deck involved in the puzzle.

After shuffling the deck and splitting it randomly in two, you count 23 cards in the left stack.

So, what is the difference between the number of red cards in the left stack and black cards in the right stack?

[Andrew]

3

[MegaMarbler]

Seems more like simple math than a riddle

[Don.Gato]

Meh unless I am missing something, this riddle is impossible. It could be said what the difference is LIKELY to be, but that isn't the question. Of course the obvious answer to that would appear to be 3, but since we are dealing with probability now it must be pointed out that despite the distribution of colored cards being 50-50, the probability of the color distribution staying the same when the randomly ordered deck is split randomly in two is quite low.


Definitely NOT simple math.

[MegaMarbler]

I was referring to Andrews answer

[Don.Gato]

I just figured it out. 3 is after all the correct answer. I was mistakenly assuming that the actual numbers of red/black cards would effect the answer.

The number of red cards in the left pile, and the number of black cards in the right pile can be determined in the following equation. Basically, the total number of red cards (26) minus the number of red cards in the left pile (x) tells you how many red cards are in the right pile. By subtracting that number from the total number of cards in that pile (29) you determine the number of black cards in the right pile.

29 - (26 - x) = y

Now we could try it for every possible value of x, there's only 24 possibilities anyway. Or we could use more math and simplify the equation. (excuse the inefficient and generally crappy way I did this, I haven't done anything like this in years. I was improvising)

29 - (26 - x) = y

29 = y + (26 - x)

- y + 29 = 26 - x

- y = - 3 - x

y = x + 3


.... and we get this:
y - x = 3

which proves that the difference between black cards in the right pile (y) and red cards in the left pile (x) is = to 3.




In other words I greatly overcomplicated matters, and Andrew was right.

[Don.Gato]

bump. Where are you j@ck?

[Oaky]

These are some great riddles (slash algebra ). Double bump!