All Questions
Huỳnh Anh Phương
04/10/2018 at 05:32-
It's easy!
The sum of the deominator and the numerator is constantly 1807.
So, \(?\) is \(\dfrac{15}{1792}\).
Huỳnh Anh Phương selected this answer.
Linh Đậu Nguyễn Huyền
03/10/2018 at 14:26-
We have:
\(a^2+b^2+c^2\ge ab+bc+ca\)
The "=" happen when and only when a = b = c
Applying the Cauchy-Schwarz inequality, we have:
\(\dfrac{1}{a^2+2}+\dfrac{1}{b^2+2}+\dfrac{1}{c^2+2}\le\dfrac{\left(1+1+1\right)^2}{a^2+b^2+c^2+2+2+2}\le\dfrac{9}{ab+bc+ca+6}=\dfrac{9}{9}=1\)
So......................
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Huỳnh Anh Phương
02/10/2018 at 10:21-
? is \(\dfrac{386}{862}\).
Huỳnh Anh Phương selected this answer.
Ngdduong1412
30/09/2018 at 13:51-
Huy Toàn 8A (TL) 02/10/2018 at 06:00In 6 days, every day do 8h need the number of people is :
6 . 9 : 6 = 9 (people
In 6 days, every day do 9h need the number of people is:
9 . 8 : 9 = 8 (people)
The answer is : 8 people
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Huỳnh Anh Phương
30/09/2018 at 11:13-
There are: 3*8*4=96 combinations that Billy can make. Huỳnh Anh Phương selected this answer.
such that 
is divisible by 
.-
There are: \(3\times2\times5=30\)combinations
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