Number Theory

If a number is divided by 15 , it leaves a remainder of 7. If thrice the number is divided by 5,then what is the remainder ???

Ans. - 1 why ?

Confusion here =>

N/15 = 15k + 7

Multiplying both side by 9

3N/5 = 5 (27k)+63 ;

3N/5 = 5 K + 3 ;

so remainder should be 3


What to do??

Quote:

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Originally Posted by timkuc

If a number is divided by 15 , it leaves a remainder of 7. If thrice the number is divided by 5,then what is the remainder ???

Ans. - 1 why ?

Confusion here =>

N/15 = 15k + 7

Multiplying both side by 9

3N/5 = 5 (27k)+63 ;

3N/5 = 5 K + 3 ;

so remainder should be 3


What to do??

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You should have N=15k+7

and then 3N=45k+21

and so 3N=5 (9k+4) + 1.

shame on me.. hattttt



btw thanks

, so it follows that .


Therefore, so a remainder of 1 results.