RMO over now time for easy problems

Algebra Level 2

$log_{15}$ . $m$ =2

Find ( $m$ ) $mod7$

2 solutions

Sujoy Roy
Dec 7, 2014

$\log_{15}m=2$ or, $m=15^2=225$ .

Now, $m \mod 7= 225\mod 7 = \boxed{1}$

Note that $15^{2} = (1+14)^{2} \equiv 1^{2} \mod 7$ .

Jake Lai - 6 years, 6 months ago

C'mon dude! Dividing 225 by 7 isn't abig task actually.

Pranjal Jain - 6 years, 6 months ago

15mod7 dude

Wasim Kamal Emon Ratul - 5 years, 2 months ago

Yeah!!!!! It isn't

Jai Gupta - 6 years, 5 months ago

Vineet PaHurKar
May 2, 2016

So M=225. Then 225mod 7 is 1