A very tricky math question with factorial

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  • Опубликовано: 23 янв 2025

Комментарии • 51

  • @henkn2
    @henkn2 4 месяца назад +21

    6! = 2*3*4*5*6 = (2*4)*(3*5*6) = 8*90 =8*9*10. So 6!*7! =7!*8*9*10 = 10!. Not really very tricky

  • @words44
    @words44 4 месяца назад

    Hi! I appreciate all the work you do especially the analysis of a problem so that at the end of your videos I can solve the problem like this one here on my own. Again thanks!

  • @ivanrakic7378
    @ivanrakic7378 4 месяца назад +1

    At 10:15, there is written that x=1*2*3...10, but actually x!=1*2*3...10. Probably it was a typo. Btw, pretty intresting task and solution.

  • @BDsobjikitchen
    @BDsobjikitchen 4 месяца назад +8

    Baby question

  • @chasr1843
    @chasr1843 4 месяца назад

    I am watching this channel just to see how long you can take to solve look-see problems

  • @Gnowop3
    @Gnowop3 4 месяца назад +2

    If you asked me to guess for the answer: 1. The answer will be bigger than 7! But less than 11! And reason is obvious 2. Half of 6 added to 7 is the number (which is 10) I will start for inspection.

  • @shoutplenty
    @shoutplenty 4 месяца назад +4

    why is this 10 mins long

    • @jursamaj
      @jursamaj 4 месяца назад +1

      Because if it was as short as it should be, it wouldn't get much ad revenue.

    • @Thatcaffeinatedgirl
      @Thatcaffeinatedgirl 4 месяца назад +1

      Also because some people need time to grasp.

    • @jursamaj
      @jursamaj 4 месяца назад +2

      @@Thatcaffeinatedgirl Nobody needs 10 minutes to grasp that 6!=8*9*10.

  • @zdrastvutye
    @zdrastvutye 4 месяца назад

    10 fx=1:for x=1 to 20:fx=fx*x:dg=1:for a=1 to 6:dg=dg*a:next a:df=dg^2*7/fx
    20 df=(df-1)/df:if abs(df)
    run in bbc basic sdl and hit ctrl tab to copy from the results window

  • @bookert2373
    @bookert2373 4 месяца назад +4

    Divide both sides by 7!, so 6! = x(x-1)…etc., a product of consecutive integers, each greater than 7. Since 6! =720 and the first integer bigger than 7 is 8, we divide 720 by 8 to get 90, which immediately factors into 9 and 10, so the consecutive integers are 8,9,10 and therefore x = 10.
    I would remove the words “very” and “tricky” from the title of this video.

  • @Christo1518
    @Christo1518 3 месяца назад

    First of all, note that 6! = 720
    1. Now, rewrite our problem: 7! * 720 = X!
    2. Which is to say: 7! * (8 * 9 * ...) = X!
    3. Find the sequence of whole numbers, starting with 8, which multiply to 720
    4. (8 * 9 * 10) = 720 = 6!
    Therefore: 6! * 7! = 10!

  • @mustfafiras8116
    @mustfafiras8116 4 месяца назад

    التوافق والتبادل

  • @jpptubie
    @jpptubie 4 месяца назад

    He’s taken 10 mins to go through the solution that could have taken 2 minutes.

  • @chrisjust7445
    @chrisjust7445 4 месяца назад

    But how would you find x for any value of a & b for: a! * b! = x!
    At first I thought he was going to multiply both sides by 7 to get 7!^2 = 7x! and then do some other magic...

  • @Ken.-
    @Ken.- 4 месяца назад

    I don't understand why you think that is the only one when it's easy to find others.

  • @Segalmed
    @Segalmed 4 месяца назад +4

    Nothing tricky there: 6! = 2*3 * 5 * 2*2 * 3 * 2. Rearrange the prime factors to 5*2 * 2³ * 3² = 10 * 9 * 8. Combine that with 7! and you get 10! => x=10.

    • @henkn2
      @henkn2 4 месяца назад

      6! = 2*2*3*2*2*5*2*6 ? You mean 2*3*4*5*6, I hope.

    • @Segalmed
      @Segalmed 4 месяца назад

      @@henkn2 Thanks for the correction. I'll edit.

  • @sundareshvenugopal6575
    @sundareshvenugopal6575 4 месяца назад

    10!

  • @antoinegrassi3796
    @antoinegrassi3796 4 месяца назад

    Je partage la plupart des commentaires. Pourquoi ne pas dire simplement qu'on a déjà tous les facteurs jusqu'à 7 grâce à 7 ! Et qu'il ne nous reste plus qu'à voir si avec TOUS les facteurs de 6 !, on arrive à compléter un factoriel. On va donc essayer de trouver un facteur 8 puis 9 puis 10 etc.
    On constate rapidement que 6! = 2×3×4×5×(2×3)
    = (2×4)(3×3)(2×5) = 8×9×10
    Donc 6!×7! = 10! donc x = 10.
    Dommage, car ce tuto est clairement et proprement présenté mais une rédaction aussi lourde est à bannir. Elle donne l'impression d'un exercice très compliqué alors qu'il est plutôt simple.

  • @RealQinnMalloryu4
    @RealQinnMalloryu4 4 месяца назад

    42 6^7 6^7^1 6^1^1 3^2^ (x ➖ 3x+2).

  • @CrashCarlisle
    @CrashCarlisle 4 месяца назад

    10. Easy

  • @oahuhawaii2141
    @oahuhawaii2141 3 месяца назад

    x! = 6!*7! = 720*7! = 10*9*8*7! = 10!
    x = 10

  • @cyruschang1904
    @cyruschang1904 4 месяца назад

    6! = 2x3x5x2x2x3x2 = 8x9x10
    6! x 7! = 10!

  • @iuliusv
    @iuliusv 4 месяца назад

    that was lucky

  • @vencik_krpo
    @vencik_krpo 4 месяца назад

    This isn't tricky. you take out 2x4 = 8 from 6! and you get 8! from the 7!. The rest is 3x5x6 = 3x30 = 90 = 9x10, so you get 10! = x!, x = 10. I didn't even need to write it down.

  • @IITJEEAspirant2025-fj6hj
    @IITJEEAspirant2025-fj6hj 4 месяца назад

    (6!×6!)×7=(6!)²7
    =6! × 7 (1×2×3×4×5×6) = 6! × 7 × (1×2×3×2²×5×2×3)
    =6! × 7 × (2⁴×3²×5)
    =6! × 7 × 8 × 9 × 10
    =10! (very easy question just need simple algebraic manipulation and rearrangement of terms that's all)
    Took 1 minute to write and seconds to solve

  • @Yasar_Kuzoluk
    @Yasar_Kuzoluk 4 месяца назад

    X=10

  • @RyanLewis-Johnson-wq6xs
    @RyanLewis-Johnson-wq6xs 4 месяца назад +3

    6!*7!=10!=3628800 x=10 final answer

  • @mircoceccarelli6689
    @mircoceccarelli6689 4 месяца назад

    6! = 1 × 2 × 3 × 4 × 5 × 6 =
    = ( 2 × 4 ) × ( 3 × 5 × 6 ) =
    = 8 × 90 = 8 × 9 × 10
    7! × ( 8 × 9 × 10 ) = 10! = x!
    x = 10
    😁👍👋

  • @markobasej8636
    @markobasej8636 4 месяца назад +2

    Only one, really. 6!=5!•3!

  • @ManojkantSamal
    @ManojkantSamal 4 месяца назад

    6!=1×2×3×4×5×6
    7!=1×2×3×4×5×6×7
    6!×7!=1×2×3×4×5×6×1×2×3×4×5×6×7
    =(1×1)×2×3×4×5×6×1×2×3×(2×2)×5×(2×3)×7
    =(1×1)×2×3×4×5×6×7×(2×2×2)×(3×3)×(2×5)
    =1×2×3×4×5×6×7×8×9×10
    =10!
    As per question
    X!=6!×7!
    =10!
    X=10

  • @googlestore4830
    @googlestore4830 4 месяца назад +3

    Why a 10-minute video on something I can solve in a few seconds by simply looking at the thumbnail? Is it so that everyone actually clicks on the video to write a similar comment, therefore you earn social engagement and promotion of your channel? Is it?

  • @hangthuy458
    @hangthuy458 4 месяца назад

    7!×6!=x!
    7!×6×5×4×3×2×1=x!
    7!×2×3×5×4×3×2×1=x!
    7!×8×9×10=x!
    10!=x!
    X=10

  • @AsifAhammad-uy1cy
    @AsifAhammad-uy1cy 4 месяца назад +1

    Tao valo lets say aschorjo

  • @benjaminkarazi968
    @benjaminkarazi968 3 месяца назад

    Hello,🌴
    6i*7i-(10i)=0, Not! 6i*7i=-42, 6i*7i-(10i)=--42-10i, not 0, zero why? 6i=1*2*3*4*5*6=720, 7i=1*2*3*4*5*6*7=5040,16i*7i=720*5040=3628800, 10i=1*2*3*4*5*6*7*8*9*10=3628800, 720*5040=3628800=10i!
    i or √-1 is a deceiving unit! √-1 has no valid value.
    Thank you for your video.💯