Featured Questions

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Cloud moderators
12/12/2017 at 16:37
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The net of a square pyramid, shown here, is a square with an equilateral triangle on each of its sides. The side length of the square can be expressed as 6x – 6 or 2x + 14, for the same value of x. When the net is folded to form a square pyramid, its surface area can be expressed in simplest radical form as a\(^2\)( b + c). What is the value of  + b + c?
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Cloud moderators
12/12/2017 at 16:38
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The product of the 3-digit number ABC and its reverse, CBA, is 140,209. If A, B and C each represent a different digit, what is the value of A + B + C? 

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dunglamtoan
13/12/2017 at 08:24
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Suppose f(x) is a polynomial of x.If f(x) has a remainder of 3 when it is divided by 2(x-1) and 2f(x) has a remainder of -4 when it is divided by 3(x+2).Thus when 3f(x) í divided by 4(\(x^2\) +x-2),the remainder is ax+b,where a and b are constants.Then a+b=...............

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Kaya Renger Coodinator
13/12/2017 at 13:05
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Find m,n are positive integer satisfy $m^6=n^{n+1}+n-1$

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Cloud moderators
13/12/2017 at 16:32
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A box contains 15 slips of paper, each bearing a different natural number from 1 to 15, inclusive. If three of these slips are randomly drawn, one at a time, without replacement, what is the probability that three consecutive numbers are drawn in increasing order? Express your answer as a common fraction

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Cloud moderators
13/12/2017 at 16:32
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Ali gives Stan a closed box that contains at least one of each token worth 5, 11 or 19 points. Ali says that the tokens have a combined value of 56 points. How many tokens are in the box?
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    Lê Quốc Trần Anh Coodinator 29/12/2017 at 17:45

    It is impossible to combine only 2 different-value tokens because 5+19, 11+19, 5+11 \(⋮̸\) 56

    Add three different tokens we have: \(5+11+19=35\left(points\right)\)

    We have: \(56-35=21\) (points) left when we add two tokens.

    Because 21 points worth 2 5-point tokens and a 11-point token so in the box, there are:

    + 3 5-point tokens

    + 2 11-point tokens

    + 1 19-point tokens

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    FA Liên Quân Garena 30/12/2017 at 21:48

    it is impossible to combine only 2 different-value tokens because 5+19, 11+19, 5+11 ⋮̸

     56

    Add three different tokens we have: 5+11+19=35(points)

    We have: 56−35=21

     (points) left when we add two tokens.

    Because 21 points worth 2 5-point tokens and a 11-point token so in the box, there are:

    + 3 5-point tokens

    + 2 11-point tokens

    + 1 19-point tokens


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Cloud moderators
13/12/2017 at 16:32
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The mean, the median and the mean of all modes of the integers 7, 4, 5, 6, 5, x are equal. How many possible values are there for x?
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    Lê Quốc Trần Anh Coodinator 29/12/2017 at 17:50

    Whatever x is, the median will still be 5 or 6 (If x > 5 than the median is 5 and 6, if x < 5 than the median is 5 and if x = 5 than the median will be 5). So there will be 2 possible values for x.

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    FA Liên Quân Garena 30/12/2017 at 21:49

    Whatever x is, the median will still be 5 or 6 (If x > 5 than the median is 5 and 6, if x < 5 than the median is 5 and if x = 5 than the median will be 5). So there will be 2 possible values for x.


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Cloud moderators
13/12/2017 at 16:30
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Xera and Yeta use this method to decide who will sit in the front passenger seat of the car. Xera throws a standard six-sided die, after which Yeta picks a card from a standard deck of 52 cards, with replacement. They continue to take turns die-throwing and card-picking until either Xera wins by rolling a four or Yeta wins by picking a card with a four. What is the probability that Yeta wins? Express your answer as a common fraction.
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    Lê Quốc Trần Anh Coodinator 29/12/2017 at 17:57

    The probability that Xera has a four is: \(1:6=\dfrac{1}{6}\)

    The probability that Yeta has a four is: \(4:52=\dfrac{1}{13}\) (A standard deck has 4 cards of four)

    So the probability that Yeta wins is: \(\dfrac{1}{13}:\left(\dfrac{1}{6}+\dfrac{1}{13}\right)=\dfrac{6}{19}\)

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    FA Liên Quân Garena 30/12/2017 at 21:49

    The probability that Xera has a four is: 1:6=16

    The probability that Yeta has a four is: 4:52=113

     (A standard deck has 4 cards of four)

    So the probability that Yeta wins is: 113:(16+113)=619


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Cloud moderators
18/12/2017 at 08:51
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Given the expression  \(\dfrac{n^2-9}{n^2-4}\)  , for how many positive integers n from 1 to 2016, inclusive, is the GCF of the numerator and denominator greater than 1?

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Cloud moderators
18/12/2017 at 08:53
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The digital clock shown can display up to four digits to represent the hour and the minute. For how many minutes in a 12-hour period does the digit 0 appear on the clock? undefined