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In a hour, two person can dig:
3 : 6 = 1/2 [hole]
Speed of Tom is:
\(\dfrac{1}{2}\div\left(2+1\right)\cdot2=\dfrac{1}{3}\left(holes\text{/}hour\right)\)
So Tom need \(12:\dfrac{1}{3}=36\left(hours\right)\) to dig 12 holes
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Let O be the center of the circle, then \(\widehat{AOC}=2\widehat{ABC}=2.30^0=60^0\)
The answer is : \(12\pi.\dfrac{60}{360}=2\pi\) (in)
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Calculate(v), not "calculator"(n) or "calculating"(v-ing)
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Unknown account 07/04/2018 at 11:31
Calculating not "caculator" :)
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Alone 14/06/2018 at 01:07
\(\dfrac{x}{8}=\dfrac{y}{3}=\dfrac{z}{10}\Rightarrow\dfrac{x^2}{64}=\dfrac{xy}{24}=\dfrac{yz}{30}=\dfrac{zx}{80}=\dfrac{xy+yz+zx}{24+30+80}=\dfrac{1206}{134}=9\)
\(\Rightarrow x^2=64.9=8^2.3^2\Rightarrow x=\pm24\)
With x=24 then y=24:8.3=9;z=30
With x=-24 then y=-9;z=-30
Lê Quốc Trần Anh selected this answer. -
Nguyễn Mạnh Hùng 15/06/2018 at 01:35
We have:
\(\dfrac{x}{8}=\dfrac{y}{3}=\dfrac{z}{10}\)
\(\Rightarrow\dfrac{x^2}{64}=\dfrac{xy}{24}=\dfrac{yz}{30}=\dfrac{xz}{80}\)
Apply the same sequence properties, we have:
\(\dfrac{x^2}{64}=\dfrac{xy}{24}=\dfrac{yz}{30}=\dfrac{xz}{80}=\dfrac{xy+yz+xz}{24+30+80}=\dfrac{1206}{134}=9\)
So \(x^2=9.64=576\)\(\Rightarrow x=24\)
\(\dfrac{xy}{24}=9\Rightarrow xy=24.9=216\Rightarrow y=9\)
\(\dfrac{yz}{30}=9\Rightarrow yz=270\Rightarrow z=30\)
So \(\left(x;y;z\right)=\left(24;9;30\right)\)
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Cristiano Ronaldo 03/08/2018 at 14:12
Do you cake??
Do you fish??
Answer: No, I don't
Yes , I do
Nobitashshs selected this answer.
Quoc Tran Anh Le Coordinator
31/08/2018 at 07:04
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Nguyễn Viết Trung Nhân 23/03/2020 at 03:30
Ali's smallest number is:
5 - 1 = 4
The total of Ben's numbers is:
128 - {[4 + (4 + 4)] x 5 : 2} = 98
Ben's largest number is:
98 : 7 + 3 = 17
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Trịnh Đức Phát 22/03/2017 at 12:44Run my EDM 15 hour before (21:01)
a + b + c = 72, then there's an even number and two odd numbers.
The only even prime number is 2, so a = 2.
b+c=70=3+67=7+61=11+59=17+53=23+47=29+41Ans : a = 2 and (b;c)∈{(3;67);(67;3);(7;61);(61;7);(11;59);(59;11);(17;53);(53;17);(23;47);(47;23);(29;41);(41;29)}
Thao Dola selected this answer. -
Run my EDM 21/03/2017 at 21:01
a + b + c = 72, then there's an even number and two odd numbers.
The only even prime number is 2, so a = 2.
\(b+c=70=3+67=7+61=11+59=17+53=23+47=29+41\)Ans : a = 2 and \(\left(b;c\right)\in\left\{\left(3;67\right);\left(67;3\right);\left(7;61\right);\left(61;7\right);\left(11;59\right);\left(59;11\right);\left(17;53\right);\left(53;17\right);\left(23;47\right);\left(47;23\right);\left(29;41\right);\left(41;29\right)\right\}\)
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