document.write( "Question 53236: Find least no in which when divide by 5,7,9 then it leaves remainder 1,2,3 respectively. What is logic for solving this problem. \n" ); document.write( "
Algebra.Com's Answer #35476 by venugopalramana(3286)![]() ![]() You can put this solution on YOUR website! Find least no in which when divide by 5,7,9 then it leaves remainder 1,2,3 respectively. What is logic for solving this problem. \n" ); document.write( "I AM NOT SURE HOW FAR YOU STUDIED ON THEORY OF NUMBERS..SO LET ME GIVE YOU A \n" ); document.write( "COMMONSENSE APPOACH.......AND DOWN BELOW BASED ON THEORY OF NUMBERS \n" ); document.write( "LET THE NUMBER BE .....N \n" ); document.write( "N-1|5............N= 5M+1...WHERE M IS AN INTEGER.............1 \n" ); document.write( "N-2|7............5M+1-2|7.....5M-1|7...........5M-1=7P......2 \n" ); document.write( "N-3|9............5M-2|9......5M-2=9Q........................3 \n" ); document.write( "NOW USE EQN.3 BY GIVING Q INCREASING VALUES AND TESTING EQN 2.NOTE THAT P,Q,M,N SHOULD ALL BE INTEGERS. \n" ); document.write( "I.TRY..Q=2.........5M-2=9*2=18.....M=4....BUT THIS CANT SATISFY EQN2 \n" ); document.write( "NEXT JUMP WILL BE TO Q=2+5=7 \n" ); document.write( "II.TRY.Q=7.........................M=13....NO(NOTE THAT M INCREASES IN STEPS OF 9...FOR Q INCREASIN IN STEPS OF 5) \n" ); document.write( "III..Q=12..........................M=22.......NO \n" ); document.write( "IV...Q=17..........................M=31......YES..5*31-1=154|7=22 \n" ); document.write( "SO........... N=5*31+1=156.. \n" ); document.write( "------------------------------------------------------------------------- \n" ); document.write( "BASED ON CONGRUENCE MODULO \n" ); document.write( "(5,7)=(5,9)=(7,9)=1 HENCE THERE IS A SOLUTION. \n" ); document.write( "N = 1(MOD 5)=2(MOD 7) = 3(MOD 9) \n" ); document.write( "N= 1+5M..... \n" ); document.write( "1+5M=2(MOD 7) \n" ); document.write( "5M = 1(MOD 7)....ADD 0 =14(MOD 7) TO BOTH SIDES \n" ); document.write( "5M = 15 (MOD 7) \n" ); document.write( "M = 3 (MOD 7) \n" ); document.write( "M = 7P+3 \n" ); document.write( "N = 1+5(7P+3)=1+35P+15=35P+16 \n" ); document.write( "35P+16 = 3 (MOD 9) \n" ); document.write( "35P = -13 (MOD 9).......ADD 0=153(MOD 9) \n" ); document.write( "35P=140(MOD 9) \n" ); document.write( "P=4(MOD 9)=9Q+4 \n" ); document.write( "N= 35P+16 = 35(9Q+4)+16=315Q+156 \n" ); document.write( "HENCE WE GET DIFFERENT SOLUTIONS FOR THE CONGRUENCIES BY PUTTING Q=0,1,2...ETC \n" ); document.write( "N= 156,571,786...ETC... \n" ); document.write( "LEAST VALUEOF N IS 156 AS GOT BOVE. \n" ); document.write( " \n" ); document.write( " |