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question mark

if 1399 is divided by 81 then the remainder is divisible by -
i) 5 ii) 3 iii) 7 iv) 11 .

shreyam maity , 11 Years ago
Grade 11
anser 1 Answers
Krishnaprasad

Last Activity: 11 Years ago

We can write 13 = 4x+1, where x=3;
We know that 81 is equal to 34=x4
 
1399 = (4x+1)99
        = 99C0(4x)99 + …...................... + 99C(4x)+99C2(4x)99C1(4x)+1
 
All the terms except the last two will get cancelled when 1399 is divided by 81.
So, if we divide the last two terms by 81, we will get the remainder required.
 
99*12 +1 = 1189 which on division with 81 gives remainder 55.
So the remainder is divisible by 5 and 11
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