All Questions

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Lê Quốc Trần Anh Coodinator
04/07/2018 at 02:53
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A cup contains 6 ounces of milk. Two ounces of chocolate syrup are added to the cup and thoroughly mixed. Then 2 ounces of that mixture are poured out. How many ounces of chocolate syrup are in the remaining mixture? Express your answer as a mixed number. 

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Lê Quốc Trần Anh Coodinator
04/07/2018 at 02:52
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If 2015 = 101a + 19b, for positive integers a and b, what is the value of a + b? 

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Lê Quốc Trần Anh Coodinator
04/07/2018 at 02:52
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When rolling two fair, eight-sided dice, each with faces numbered 1 through 8, what is the probability that the two numbers rolled have a sum of 9? Express your answer as a common fraction. 

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Huỳnh Anh Phương
03/07/2018 at 14:12
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What is the perimeter of ABCD?

B A C D 8cm 4cm


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LOL
03/07/2018 at 13:46
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A trapezium ABCD has two paralell sides AB and CD. The diagonals AC and BD intesect at E. If the areas of triangles CDE and CDB are 1 and 4 respectively, what is the area of trapezium ABCD? 

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Summer Clouds moderators
10/10/2017 at 08:44
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In trapezoid ABCD with AB parallel to CD, the diagonals AC and BD
intersect at E. If the area of triangle ABE is 50 square units, and the
area of triangle ADE is 20 square units, what is the area of trapezoid ABCD?
 
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    Phan Thanh Tinh Coodinator 10/10/2017 at 11:08

    A B C D E H K M N

    Draw \(AH,CK\perp BD;AM,BN\perp CD\)

    \(\dfrac{S_{ABE}}{S_{ADE}}=\dfrac{AH.BE:2}{AH.DE:2}=\dfrac{BE}{DE}\Rightarrow\dfrac{BE}{DE}=\dfrac{50}{20}=\dfrac{5}{2}\)

    \(\Rightarrow\dfrac{S_{BEC}}{S_{DEC}}=\dfrac{BE.CK:2}{DE.CK:2}=\dfrac{BE}{DE}=\dfrac{5}{2}\)

    \(\dfrac{S_{ADC}}{S_{BDC}}=\dfrac{AM.DC:2}{BN.DC:2}=1\Rightarrow S_{ADE}+S_{DEC}=S_{BEC}+S_{DEC}\)

    \(\Rightarrow S_{ADE}=S_{BEC}=20\left(units^2\right)\)

    \(\Rightarrow S_{DEC}=20:\dfrac{5}{2}=8\left(units^2\right)\)

    So, the answer is : \(20+50+20+8=98\left(units^2\right)\)

    Selected by MathYouLike

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Uchiha Sasuke
03/07/2018 at 01:59
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Given triangle ABC with AH = 8 cm, BC = 20 cm. The area of the triangle ADE is ... cm2

A B C D E H


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Lê Quốc Trần Anh Coodinator
02/07/2018 at 03:01
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Of 600 students at Goodnight Middle School in Texas, 85% are not native Texans. Of those non-native students, 60% have lived in Texas more than 10 years, and 30 students have lived in Texas less than a year. How many non-native students have lived in Texas for at least 1 year but not more than 10 years? 
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    Nguyễn Mạnh Hùng 02/07/2018 at 08:32

    We have: 30 students have lived in Texas less than a year 

    => There are 5% students of 600 students at Goodnight Middle School in Texas have lived here less than 1 year.

    So there 65% students are not native Texas lived here less than a year and more than 10 years.

    But there are 85% are not native Texas 

    => The non-native students have lived more than 1 year but less than 10 year is 20% = 120(students)

    Selected by MathYouLike

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Lê Quốc Trần Anh Coodinator
02/07/2018 at 03:01
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Currently, the sum of the ages of Yumi, Rana and Victoria is 42 years. Four years ago, the sum of the ages of Rana and Victoria was equal to the current age of Yumi. What is Yumi’s current age?
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    Nguyễn Mạnh Hùng 02/07/2018 at 08:39

    Call Yumi's age is a

    Rana's age is b

    Victoria's age is c.

    We have: a + b + c = 42 

    => ( a - 4 ) + ( b - 4 ) + c = 36

    But a - 4 + b - 4 = c 

    => a + b = c + 8 (1)

    We also have: a + b + c = 42

    => a + b = 42 - c (2)

    From (1) and (2) we have:

    42 - c = c + 8

    => 42 - 8 = 2c

    => 36 = 2c

    => c = 18

    So current Yumi's age is 18.

    Selected by MathYouLike

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Lê Quốc Trần Anh Coodinator
02/07/2018 at 02:58
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A square residential lot is measured to be 100 feet on each side, with a possible measurement error of 1% in each of the length and width. What is the absolute difference between the largest and smallest possible measures of the area given this possible error?