Question

Last three digits of 15^2021 are​

Answer 1

HELLO DEAR,

QUESTION:- To find last three digits of 15^2021?

SOLUTION:- To find the last three digits ,we have to first find a relation by doing 15^x ( where x = natural number) and making some logics .

Lets start,

15^1 = 15

15^2= 225

15^3= 3375

15^4= 50625

15^5= 759375

15^6= 11390625

15^7= 170859375

from above we can see that at the unit place any power of 15 gives 5.

And at the ten place ,if the power at 15 is even it gives 2, otherwise if power is odd it gives 7.

And also at hundred place ,if the power at 15 is even it gives 6,otherwise if power is odd it gives 3.

So, 15^2021 have odd power

Therefore we write at one place is 5

At ten place is 7

At hundred place is 3.

Therefore last three digits of 15^2021 => 375.

ANSWER => 375

I HOPE IT'S HELP YOU DEAR,

THANKS.