Divides by 143?

( 11221133112211 ) 12 \large (11221133112211)_{12}

Is the above number divisible by ( 143 ) 10 ? (143)_{10}? (No calculators should be necessary!)


Clarification: The subscript 12 indicates we are working in base 12.


Try more questions on bases .
Yes No

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.

1 solution

Geoff Pilling
Apr 29, 2016

In order to be divisible by 14 3 10 143_{10} , the number must divide 1 1 10 11_{10} and 1 3 10 13_{10} , since, in decimal, 143 = 11 13 143 = 11*13 .

Now, let e = ( even digits ) e = \sum (\textrm{even digits}) and let o = ( odd digits ) o = \sum (\textrm{odd digits}) and let s = e + o s = e+o .

A number is divisible by 13 13 in base 12 12 if ( e o ) (e-o) divides 13 13 .

And a number is divisible by 11 11 in base 12 12 if the sum of the digits is divisible by 11 11 .

In this case e = 11 e = 11 and o = 11 o=11 , so e o = 0 e-o=0 , which divides 13 13 , so the number divides 13 13 .

Also, s = e + o = 22 s=e+o=22 which divides 11 11 , so the number divides 11 11 .

Since the number divides both 11 11 and 13 13 , the answer is... Y e s \boxed{Yes} , the number is divisible by 143 143 .

Same way here. It is an analogy of divisibility rule of 9 9 and 11 11 in base ten.

展豪 張 - 5 years, 1 month ago

I bashed everything in base 10

Debarghya Adhikari - 1 year ago

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...