Long chain of remainders ( m o d 11 ) \pmod{11}

Find the remainder of 2014.2015.2016.................2023 2014.2015.2016.................2023 on division by 11 11 .


The answer is 10.

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

2 solutions

We know that both 2013 and 2024 are both divisible by 11. Thus all the numbers lying in between will have remainder 1, 2,...10.

According to wilson's theorem:

(p-1)!=-1(modp)

,here we have 1.2.3.....9.10.

Therefore,

10! = -1 (mod11)

Both -1 and 10 are correct, but it seems that the solution given is only -1.

When asking for remainders, standard notation is to require the smallest non-negative remainder. I have updated the answer to 10.

Calvin Lin Staff - 6 years, 8 months ago

Log in to reply

but isn't the answer 4? I doubt it is true, by multiplying!

Agastya Chandrakant - 6 years, 4 months ago

don't know wilson's theorem

PUSHPESH KUMAR - 6 years, 8 months ago

Log in to reply

Actually, you can solve it even without using Wilson's theorem. Just evaluate the value of 10 ! m o d 11 10! \mod 11 by splitting up 10 ! 10! and finding the remainder of each part and then find the remainder at last of the value obtained if it is > 10 >10 like this,

10 ! = 10 × 9 × 8 × 7 2 × 1 = 90 × 56 × 30 × 24 10 ! ( m o d 11 ) = ( 90 × 56 × 30 × 24 ) ( m o d 11 ) 10 ! ( m o d 11 ) ( 2 × 1 × 8 × 2 ) ( m o d 11 ) 10 ! ( m o d 11 ) 32 ( m o d 11 ) 10 ( m o d 11 ) 10 ! ( m o d 11 ) 10 ( m o d 11 ) 10!=10\times 9\times 8\times 7\ldots 2\times1 = 90\times 56\times 30\times 24 \\ \implies 10! (\mod 11) = (90\times 56\times 30\times 24) (\mod 11)\\ \implies 10! (\mod 11) \equiv (2\times 1\times 8\times 2) (\mod 11) \\ \implies 10! (\mod 11) \equiv 32 (\mod 11) \equiv 10 (\mod 11)\\ \implies \boxed{10! (\mod 11) \equiv 10 (\mod 11)}

Prasun Biswas - 6 years, 6 months ago

Overrated!

Kartik Sharma - 6 years, 8 months ago
Razing Thunder
Jul 3, 2020
1
2
3
4
a=1
for i in range(2014,2024):
    a=a*i
print(a%11)    

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...