• Content count

  • Joined

  • Last visited


Community Reputation


About yuud

  • Rank

yuud's Activity

  1. yuud added a topic in New Logic/Math Puzzles   

    A father has 80 apples and share them between his 3 sons such that the eldest get 50 apples, the 2nd 20 and the 3rd 10.He tells to sell the apples such :
    a)each and every apple is worth the same;
    b)each son should bring the same amount of money home;
    c)all apples must be sold, and each son must sell his quota;
    d)no sharing of apples or money;
    e)no expense of money
    How much money is brought home??
    • 24 replies
  2. yuud added a post in a topic   

    • 0
  3. yuud added a post in a topic   

    So if I replace 0, I get a number divisible by 7. If I replace 1, I also get a number divisible by 7. So I've got my n and n+1 ... So n= 0, 1, 2, 3... n

    That's it???

    I thought there's a more systematic way of doing this...
    • 0
  4. yuud added a topic in New Logic/Math Puzzles   

    For what integers n is 3^(2n+1) + 2^(n+2) divisible by 7

    I understand that I have to use proving by induction but I don't know how to proceed ... Please HELP!
    • 7 replies
  5. yuud added a post in a topic   

    Yes your code is good... i tested it with other sample data...
    • 0
  6. yuud added a post in a topic   

    Cool...but i was looking for a simpler algorithm, without codes, functions, etc...
    • 0
  7. yuud added a topic in New Logic/Math Puzzles   

    Create a simple algorithm for this problem... You think it's to easy? Then do it in 5 minutes...

    The Snail
    A snail is at the bottom of a 6-foot well and wants to climb to the top. The snail can climb 3 feet while the sun is up, but slides down 1 foot at night while sleeping. The snail has a fatigue factor of 10%, which means that on each successive day the snail climbs 10% X 3 = 0.3 feet less than it did the previous day. (The distance lost to fatigue is always 10% of the first day's climbing distance.) On what day does the snail leave the well, i.e., what is the first day during which the snail's height exceeds 6 feet? (A day consists of a period of sunlight followed by a period of darkness.) As you can see from the following table, the snail leaves the well during the third day.

    (Day) (Initial Height) (Distance Climbed) (Height After Climbing) (Height After Sliding)
    1 0' 3' 3' 2'
    2 2' 2.7' 4.7' 3.7'
    3 3.7' 2.4' 6.1' -
    Your job is to solve this problem in general. Depending on the parameters of the problem, the snail will eventually either leave the well or slide back to the bottom of the well. (In other words, the snail's height will exceed the height of the well or become negative.) You must find out which happens first and on what day.


    The input file contains one or more test cases, each on a line by itself. Each line contains four integers H, U, D, and F, separated by a single space. If H = 0 it signals the end of the input; otherwise, all four numbers will be between 1 and 100, inclusive. H is the height of the well in feet, U is the distance in feet that the snail can climb during the day, D is the distance in feet that the snail slides down during the night, and F is the fatigue factor expressed as a percentage. The snail never climbs a negative distance. If the fatigue factor drops the snail's climbing distance below zero, the snail does not climb at all that day. Regardless of how far the snail climbed, it always slides D feet at night.


    For each test case, output a line indicating whether the snail succeeded (left the well) or failed (slid back to the bottom) and on what day. Format the output exactly as shown in the example.

    Sample Input

    6 3 1 10
    0 0 0 0

    Sample Output

    success on day 3
    failure on day 2
    • 5 replies