Claire Corlett

Fish Food, Fish Tanks, and More
Can you solve the fish riddle? –  Steve Wyborney

Can you solve the fish riddle? – Steve Wyborney


You are the cargo director on the maiden
voyage of the S.S. Buoyant, and you’ve agreed to transport
several tanks containing the last specimens of a critically
endangered fish species to their new aquarium. Unfortunately, as you’re passing
through shark-infested waters, the boat is battered by a fierce storm,
throwing your precious cargo overboard. And to make matters worse, no one seems certain
just how many fish tanks are missing. Fortunately, you have a rescue sub
at your disposal, but only enough fuel for one trip
to the ocean floor. You need to know where the tanks are so you can gather them all
in one quick pass. Not a single fish can be lost. You decide to scan the three sectors
of the ocean floor where the cargo could have landed. Thermal imaging shows 50 organisms
in the area, and you quickly realize that that number
includes both your fish and some ravenous sharks. You flip on the sonar
to get a better look. The image for Sector Alpha shows
four tanks and two sharks, the image for Sector Beta shows
two tanks and four sharks, and the image for Sector Gamma
is blank. Your sonar has malfunctioned, and you’re going to have to go
with the info you have. You check the shipping notes, but all you learn is that each tank
had the same number of fish inside. The cargo hold had space for anywhere
from 1 to 13 total tanks. And finally, the old captain tells you
that this area has the odd property that no two sectors can have the same
number of sharks, but every sector will have at least one, and no more than seven. There’s no time to waste. The tanks won’t withstand the pressure
much longer. As you descend in the sub,
you review everything you know. How many fish tanks do you need
to find in Sector Gamma? Hurry, the fate of an entire species
depends on you. Pause here if you want
to figure it out for yourself. Answer in: 3 Answer in: 2 Answer in: 1 At first, it seems like there are just
too many missing pieces of information. After all, you don’t know how many fish
or how many tanks there are, let alone how many fish are in each one. But then you remember the best way to compare multiple pieces
of partial information – a table. Since we know there are thirteen
tanks at most, and we already see six tanks
in Sectors Alpha and Beta, we know the total number of tanks
must be between 6 and 13. We also know that each sector has
a different amount of sharks with no more than seven in each one. Since there are two in Sector Alpha
and four in Sector Beta, Sector Gamma can have
1, 3, 5, 6, or 7 sharks. What about the number of endangered fish? Out of the 50 total organisms
in all three sectors, we know at least seven are sharks, leaving a maximum of 43 fish
inside all the tanks. And the more sharks we find in Sector 3,
the fewer fish there are to save. Now, remember that the fish are
equally distributed across all the tanks. Why is that important? Because it means that one of the possible
values for the total amount of fish must be divisible by one of the possible
values for the total amount of tanks. And looking at the table, we can see
that the only combination that works is 39 fish divided between 13 tanks
with three fish in each. With sharks swarming around, you quickly pilot the sub through
the first two sectors before retrieving the remaining
seven tanks in Sector Gamma. You’ve saved the species
and taken an impromptu dive. All in all, not a bad day,
unless you happen to be a hungry shark.

100 comments on “Can you solve the fish riddle? – Steve Wyborney

  1. the sharks: omg look at all these fish, we finally dont have to starve, all we have to do is wait for the containers to break
    some random dude: hippity hoppity these fish are now my property
    the poor shark family that doesn't have enough money to buy food: starve to death

  2. Just go rescue the fish in the first two sectors and then go to sector gamma and just rescue whatever’s there

  3. *tanks of endangered fish species got threw to the ocean
    CAPTAIN: wait, i'll solve a math problem

  4. My thoughts before watching the answer:

    I believe sector gamma contains 7 tanks and 5 sharks based on this formula:

    6x+7x+y=44
    X=3 (Meaning each tank contains 3 fish)

    6 +7 equals 13 which is the maximum number of thanks. If we multiply these numbers with 3 (fish per tank) we get:

    18 + 21 = 39

    18 + 21 + y = 44

    y = 44 – 39

    y = 5 (Number of sharks in sector Gamma)

    In that case there is a total of fish tanks are 13 and the number of sharks aren't equal to the two previous sectors while it remains a number beetween 1 and 7.

    Full solution:
    6x + 6 + xx + y = 50
    6x + xx + y = 50-6
    6x + 7x + y = 44
    _______________
    Hypothesis: X=3
    18 + 21 + y = 44
    y = 44 – 39
    y = 5

    I may be wrong but I'll leave this attempt here no matter the solution. Let's see the answer.

  5. Who’s idea was it to go through shark infested waters AND not know there’s a storm coming WHILE having endangered fish?

  6. Gamma has 5 sharks and 7 fish tanks (each with 3 fish each in them). The quick way to do it is to make a formula from a tree with speculative possible values and make logical guesses. 50 entity, fish tank is in an interval of 1 to 13 and the last tank has either +1,+3,+5,+6,+7 sharks to account while trying different factors for the number of fish in a tank. Not a native speaker and this may be unclear or too complicated for this but I solved it while typing this… lol

  7. Sooooo sector Gama has 5 shark and 7 tank so a total of 12 thing in it where alpha and beta have 6 each?

  8. Ted-ed:Hey, You have to save an entire species of fish and not a single one can be lost. But you know… NO PRESSURE.

  9. This one is just the most unrealistic scenario of the whole series with all the exceptions asumptions.

  10. This one was actually the most easiest from Ted I tried to solve, finally one I could solve with ease hh 😅😀

  11. This one was pretty simple, actually. I got it in like two minutes but thought that couldn't be it because of how simply solved it was and then went on to complicate things for like ten more minutes before I finally said went with my answer and checked to see if I was right. I was! Yay!

  12. you’re looking for 7 tanks in gamma, with 13 tanks total, 3 per fish

    i’ll check my answer once i finish the video

  13. The riddle looks like a typical day at work for me. And I still have no answers here or there. Anyway…

  14. All who got it correct should get 200 out of 100. One for guessing the question and another for answer.

  15. Anyone else notice that at the beginning of the video he said that we agreed to take seven fish tanks on the trip and later on he said there was 13 total fish tanks that fell.

  16. I actually managed to solve it myself! But I didn't make a table, I just did it by trial and error to see how many fish would make sense- from 44, to 43, 42, 41, 40 and finally 39 on the sixth guess (divided by 3 of course).

  17. Such a victory when I solve one! But then I see how you’re “supposed” to solve it and I just get a headache lol

  18. According to YouTube comments on another video, I am an hungry shark and this results displease me

  19. I feel so proud! I finally solved this! With the power of algebra, millions of trial and error and eternity upon eternity.

  20. I thought the answer was 4 sharks and 2 tanks because I thought each tank contained 5 🐠:
    Sector Alpha- 2 sharks and 4 tanks(4×5=20 🐠)
    Sector Beta- 4 sharks and 2 tanks (2×5= 10 🐠)
    [now there are 36 creatures because: 20 🐠 +10 🐠 +6 🦈 =36]
    So Sector Gamma- 4 sharks and 2 tanks.
    That way —> 36 creatures in the first and second sectors + 14 (2 tanks x5= 10 🐠+4 🦈 =14)=50 creatures.
    :/

  21. If the fish are critically endangered than shouldn't some be put in safer places? Why transfer all of them to a aquarium?
    "You have just enough fuel to make one trip to the ocean floor"
    Oh well. Should have refueled, huh?

  22. I used around 5 minutes to work out…
    so the number of sharks in the sector gamma can be 1,3,5,6,7
    Considering the number of fish must not be a prime number, and there are already 6 tanks.
    Only when the number of sharks in sector gamma is 5 or 6, the number of fish appears to be a composite number.
    When it’s 6, the number of fish will be 38=19*2 we can’t have neither 19 tanks or 2 tanks total
    When it’s 5, the number of fish will be 39=13*3. There will be 13 tanks total and it’s the only solution.
    Therefore, the number of tanks in sector gamma will be 13-2-4=7
    I figured this out when paused at2:30

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