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

  1. 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

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

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

  4. 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.
    :/

  5. 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?

  6. 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

  7. It has to be a total of 13 tanks with 3 fish each right?? Bc that alone would make 39 fish then add the 6 sharks from sector alpha and beta and now u have 45, which brings me to the solution that in section gamma there have to be 5 remaining sharks so that there is a total of 50 fish.
    In conclusion there have to be 7 tanks and 5 sharks in sector gamma and each tank has 3 fish, add that with the number of fish of the other sectors and u have 50 fish.

  8. Guys i solved it on my own… My first…. But i used a different method… it's algebraic
    .
    .
    Let total no of fishes in each aquarium be f…
    Than 2+4f+4+2f+x+yf= 50
    where x and y r the no of sharks and no of tanks respectively
    .
    (6+y)f=44-x
    f=44-x/6+y
    Now f can't be a fraction,it can only be a whole no
    And
    x+6≤7 and x can't be 2and 4, only possible values r 1,3,5 and 6
    Subtracting by 1 and 3 gives us a prime no so impossible and by 6 gives us 38 as numerator which has to be divided by 6+y so y should be equal to 13 which is not possible.. leaving us only with 5
    Substituting this value we can get
    .
    .
    44-5/6+7=3
    Hence no of fish in each tank = 3 and total tanks in sector gamma is 7 and shark=5
    .
    Ps:- I couldn't resist myself sharing my solution and it's also the first comment i wrote… hope it doesn't goes unnoticed.

  9. NO WAY I GOT IT. I used algebra. I put the tanks in gamma to the max of being 7 tanks(13-2-4=7). Then made 39 divisible by 13. This is a confusing explanation but I still got 3 fish in each tanks, being 39 tanks. ALRIGHT

  10. You: hit storm
    Rare fish: lost
    Sharks: In water
    Cargo: In sea
    Escape ship: you in
    Actually ship: sunken
    Fuel: only 1 tank
    Radar: gone bad
    Submarine: to get fish tanks
    Tanks: less than 13
    Sharks: less than 7 in each area
    Sharks and fish: 50
    Hotel: Trivago DUH

  11. You wouldve known how many tanks you had initially, you could have counted how many tanks were left on deck after the big wave, then you would automatically know.

  12. My maths sir sent us a list of TED talks to decide on our project topic. I just saw the word ' fish' and decided to take this without watching the video. But now I can't understand the sum properly. And Maths is my least fav subject.😩

  13. There are 10 Fish in a tank, out of which 2 have drown, 4 have swim away and 3 have died.

    How many are left?

    https://youtu.be/CRioezZyRK8

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