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What is the smallest positive n under 50,000 that satisfies the following:

n mod 43 = 22
n mod 101 = 64
n mod 211 = 30 . Thanks for help.

 Feb 19, 2017

Best Answer 

 #2
avatar+12530 
+5

correction

241 : 211 = 1 R 30

 Feb 19, 2017
 #1
avatar+12530 
+5

What is the smallest positive n under 50,000 that satisfies the following:

n mod 43 = 22
n mod 101 = 64
n mod 211 = 30 . Thanks for help.

laugh

 Feb 19, 2017
 #2
avatar+12530 
+5
Best Answer

correction

241 : 211 = 1 R 30

Omi67  Feb 19, 2017
 #3
avatar
+2

Omi67: Thanks for that, but the question is about ONE NUMBER, n, that satifies those 3 conditions.

 Feb 19, 2017
 #4
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0

43A + 22 =101B + 64 =211C + 30, solve for A,B,C.
A=1,065,  B=453,    C=217, so that:
43 x 1,065 + 22 =45,817 The smallest positive number.
LCM {43, 101, 211} =916,373. So, the general form is:
916,373D + 45,817. And for D=0, 1, 2......etc. We have:
45,817 The smallest positive number.
962,190
1,878,563.......etc.

 Feb 19, 2017
 #5
avatar+26396 
+5

What is the smallest positive n under 50,000 that satisfies the following:

n mod 43 = 22 

n mod 101 = 64 

n mod 211 = 30 . Thanks for help.

 

n22(mod43)n64(mod101)n30(mod211)Let m=43101211=916373

 

43 is a prime number, and 101 is a prime number, and 211 is a prime number.

Because 43 and 101 and 211 are relatively prim ( gcd(43,101,211) = 1! ) we can go on:

 

n=22101211[(101211)φ(43)1mod43]=modulo inverse (101211)(mod43)=(101211)421(mod43)=(101211)41(mod43)=(21311(mod43))41(mod43)=(26)41(mod43)=5+6443211[(43211)φ(101)1mod101]=modulo inverse (43211)(mod101)=(43211)1001(mod101)=(43211)99(mod101)=(9073(mod101))99(mod101)=(84)99(mod101)=95+3043101[(43101)φ(211)1mod211]=modulo inverse (43101)(mod211)=(43101)2101mod211=(43101)209mod211=(4343(mod211))209mod211=(123)209mod211=199+43101211k|kZn=22101211[5]+6443211[95]+3043101[199]+43101211kn=2344210+55163840+25927710+43101211kn=83435760+916373k|kZnmin=83435760(mod916373)nmin=45817n=45817+916373k|kZ

 

The smallest positive n under 50,000 is 45817

 

laugh

 Feb 20, 2017
edited by heureka  Feb 20, 2017
edited by heureka  Feb 20, 2017
edited by heureka  Feb 20, 2017

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