Amano Ichigo
22/10/2017 at 14:47-
Luffy xyz 123 23/10/2017 at 06:28A = 2 + 22 + 23 + 24 + 25 + 26 + 27 + 28 + 29 + 210
A = 2 + 4 + 8 + 16 + 32 + 64 + 128 + 256 + 512 + 1024
Then you calculated
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Detecvite Conan 22/10/2017 at 15:57A=2+4+8+16+32+64+128+256+512+1024=2046
Divisible by 3 is the number of digits divided by 3, then divisible by 3
=> 2046:3
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Detecvite Conan 22/10/2017 at 15:56A=2+4+8+16+32+64+128+256+512+1024=2046
Divisible by 3 is the number of digits divided by 3, then divisible by 3
=> 2046:3
Answer: A:3
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Phan Văn Hiếu 29/10/2017 at 16:24\(A=2+2^2+2^3+2^4+2^5+2^6+2^7+2^8+2^9+2^{10}\)
\(2A=2^2+2^3+2^4+2^5+2^6+2^7+2^8+2^9+2^{10}+2^{11}\)
\(2A-A=\left(2^2+2^3+2^4+2^5+2^6+2^7+2^8+2^9+2^{10}+2^{11}\right)\)
\(-\left(2+2^2+2^3+2^4+2^5+2^6+2^7+2^8+2^9+2^{10}\right)\)
\(A=2^{11}-2\)
\(A=2\left(2^{10}-1\right)\)
\(\)we have \(2^{10}\)divide 3 residual 1
should \(2^{10}-1⋮3\)
\(\Rightarrow2\left(2^{10}-1\right)⋮3\)or \(A⋮3\)