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Grade 1010 grade maths

52009+132009÷8
Find the remainder
Please tell the process

Profile image of Manish soni
7 Years agoGrade 10
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2 Answers

Profile image of Arun
7 Years ago
Here, we have 5^2009 + 13^2009

We know that a^n + b^n is always divisible by (a+b) when n is odd.

2009 is an odd number.
So, 5^2009 + 13^2009 is divisible by (5+13) i.e 18.

Hence, the remainder is 0.
Profile image of Aditya Gupta
7 Years ago
Actually 5^2009= 5*25^1004 
Note that 25=8*3+1
Since remainder of 25^n when divided by 8 is 1, so remainder when 5^2009 divided by 8 is 5
Now 13^2009=13*169^1004
But 169= 8*21+1
So remainder when 13^2009 is divided by 8 is 13*1 or 13-8= 5
So net remainder is 5+5=10 or 10-8 
=2