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OpenStudy (anonymous):
oh.. nevermind, ive got it!
ganeshie8 (ganeshie8):
could you pls share the solution
OpenStudy (anonymous):
ok, let me type it up
OpenStudy (irishboy123):
.
ganeshie8 (ganeshie8):
take ur time :)
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OpenStudy (anonymous):
But I'm not sure if thats the only solution... can someone help me check pls?
ganeshie8 (ganeshie8):
That looks good! Just for the sake of an alternative :
\[\begin{align*}
x &\equiv r \pmod{6}, \\
x &\equiv 9 \pmod{20}, \\
x &\equiv 4 \pmod{45}
\end{align*}\]
From first and second congruence, notice that \(\gcd(6,20)=2\), so it must be the case that
\[r\equiv 9\equiv 1\pmod{2}\tag{a}\].
From first and last congruences, notice that \(\gcd(6,45)=3\), so it must be the case that
\[r\equiv 4\equiv 1\pmod{3}\tag{b}\]
From \((a),~(b)\) it follows \(r\equiv 1\pmod{2\cdot 3}\)
OpenStudy (anonymous):
so it is the only solution right?
ganeshie8 (ganeshie8):
Yep! there are no other solutions
OpenStudy (anonymous):
ok thank!
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