Can You Solve These Challenging Logical Puzzles?

Which way is the bus going? Skip ➡️19:07. How many of these 7 puzzles can you solve?

0:00 puzzle 1
2:15 puzzle 2
5:33 puzzle 3
8:37 puzzle 4
11:48 puzzle 5
14:59 puzzle 6
19:07 puzzle 7 bus

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Puzzle 1
Puzzle 2
sent by email, also UKMT 2015
Puzzle 3 kangaroo
Puzzle 4 stick
Puzzle 5 water
Thanks to Fahad Alomaim for the suggestion! Translated from the Mawhiba curriculum
Puzzle 6 code lock
Puzzle 7 bus

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[harzemyalcinkaya]

Puzzle 2: You don't need to think about the length of the train at all. It takes 3 more seconds to go 75 more meters of tunnel. It's simply 75/3 = 25 m/s

[sharootere]

Puzzle 5: The inserted Shape is 1/4 the volume of the water filled box. By inserting it, we take away 25% of the space, and add this to the remaining 75%. So the water raises by 4/3. 25*4/3=33.3333, and h=33.3333-25

[scoutskylar]

General solution to puzzle 4: Place a match stick so that its midpoint is on the center of the square, in any orientation. Use two more match sticks to connect either endpoint of the first match stick to the perimeter of the square in any way. Connect the other endpoint in the same way. All possible solutions that create two congruent partitions can be constructed in this way.

[דרורארז]

In puzzel 6 we only need the first 3 clues to solve, the others are redandent

[L]

21:04. Sure, there are no doors. There's also no fold-out stop sign and a bunch of other details. No reason that the absence of a door is any more noteworthy than myriad other details that are missing.

[Taikamuna]

Puzzle 7: The bus isn't moving. It is a picture

[xandon]

I love how every one of these challenging logic puzzle videos includes one puzzle that is literally just a system of linear equations.

[mstmar]

for puzzle 4, i essentially got the same answer as the first in the video, but in a different way. a 4x4 and adding 5 matches made me think of a 345 triangle. so we know that if you draw a diagonal from the bottom left corner to 1 match down from the top right, it will use exactly 5 matches. we just need to move the diagonal up half a match stick to make the halves equal. the best part about this approach is that you know where the diagonal is, not just that it exists

[byczakrew]

puzzle 6: two last clues are redundant, actually

[mstmar]

for puzzle 7, the bus looks like it's taking up the whole top half of the road. assuming it's a 2 lane bidirectional road (most roads), the top lane would be going to the left (in countries you drive on the right side of the road)

[BeaDSM]

Puzzle 4: do a 3-4-5 triangle and then shift it along by half a matchstick

[josobra]

In puzzle 4 you could do a line and put the last matchstick anywhere

[FGGiskard]

14:53 I think Puzzle 5 has a much simpler solution: you’re basically taking away 1/4 surface area so the new height must be 4/3 of the original 25cm so it must increase by 1/3*25=8, 33…

[fiercedeity]

Since the puzzle 7 solution depends on assumptions about the bus, you can also get to a conclusion of impossible to solve by making assumptions like "the only door is on the rear of the bus and flush with the frame", "the bus has no doors", or "the bus can only be entered/exited through a hole in the roof". There's also the relativistic solution of "the bus is stationary, the ground is moving beneath it without friction"

[rockerguy]

Puzzle 3 can be done in an even faster and in my opinion slightly more intuitive way. The medium sized full shape (10+3+7) also contains the central shape (4), meaning we subtract that from the total giving us 16. Then just repeat same logic for outside shape: 11+9+6+4+12 = 42, and minus 16 is 26. Took me about 10 seconds to solve it this way. The basic reasoning is the same, but it first focuses on the inner "full shape" which helps simplify the problem down because you're not looking at the full picture anymore and are instead focused on just the 4 inner shapes (3, 4, 7, 10).

Puzzle 6 can be solved after first 3 clues. 128 says 1 digit is correct and in correct position. 157 says 1 digit is correct, but in the wrong position. That already eliminates 1 as being a possible option in the code. 841 says 2 digits are correct but in wrong position. Since 1 is eliminated, 84 are the correct digits. We had 8 in the first clue where we know 1 digit is correct and in correct position, meaning the 3rd digit is 8. 4 is in incorrect position, so it's not the 2nd digit, and it can't be the 3rd digit because that's 8, meaning 4 has to be the 1st digit. The 2nd clue tells us that 1 digit is correct but in the wrong position. 1 is already eliminated. It can't be 5 because that would mean it's in the correct position. Which leaves us with 7 being the only possible 2nd digit. The code is 478. Clues 4 and 5 aren't needed at all.

[Blockenheimer]

Challenge mode: the bus is in the tunnel that goes under the english channel

[LednacekZ]

Puzzle 6: has nothing to do with what side of road you drive, it is all about what side of the bus the door is. You can drive a left side door bus in a right side road country. Plenty of UK busses do in Europe or vice versa. The bus could also go in reverse which makes the question completely obsolete.

[stur]

Puzzle 4: similar to the first solution, I know that 3, 4, 5 make a pythagorean triple. The 5 matchsticks can be placed in line from one vertex to the tip of the 3rd matchstick on an opposite side. Then 5 matchstick segment can be shifted 0.5 matchstick length to bisect the square.

[caput_in_astris]

For Puzzle 5, there is a much easier answer:
The volume of the smaller shape will displace exactly 1/4 of the water thus the height will raise to exactly 4/3 of 25 ie by 8.333 cm. 😊

[michaelgeiss]

No matter how much I look at that bus, it still looks stationary.