Count the number of 5-digit numbers (in the decimal system; integers from 1 to ) which are not divisible by 11.

So total number which is not divisible by 11 = 89999-8181 = 81819  

Step-by-step explanation:

We have to find the total numbers which are not divisible by 11 from 10000 to 99999

Total number from 10000 to 99999 = 99999-10000+1=90000

Just after 10000 the number which is divisible by 11 is 10010

And just below 99999 the number which is divisible by 11 is 99990

Using AP formula

, here a is first term, d is common difference and n is number of terms

So

n-1 = 8180

n= 8181

So total number which is not divisible by 11 = 90000-8181 = 81819

the answer is b: 18

step-by-step explanation:

use the pythagorean theorem to .

a^2+b^2=c^2

plug 18 for "r"

the 2 legs are 18 and 24

18^2+24^2=c^2

324+576=c^2

900=c^2

c=30

30-12=18

18 is the radius

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