1. Check whether 23035 is divisible by 85 or not?Solution:Divisibility rule of 85 :
If number is divisible by 5 and 17, then number is also divisible by 85.
Divisibility rule of 5 :
The last digit is 0 or 5, then number is also divisible by 5.
Last digit of 23035 is 5, which is divisible by 5.
`:.` 23035 is divisible by 5.
Divisibility rule of 17 :
5 times the last digit and subtract it from the rest of the number.
If the answer is divisible by 17, then number is also divisible by 17.
(Apply this rule to the answer again if necessary)
`2303color{red}{5}=>2303 - color{red}{5} xx 5 = 2303 -25 = 2278`
`227color{red}{8}=>227 - color{red}{8} xx 5 = 227 -40 = 187`
`18color{red}{7}=>18 - color{red}{7} xx 5 = 18 -35 = -17`
Here -17 is divisible by 17.
`:.` 23035 is divisible by 17.
23035 is divisible by 5 and 17.
`:.` 23035 is divisible by 85.
2. Check whether 28900 is divisible by 85 or not?Solution:Divisibility rule of 85 :
If number is divisible by 5 and 17, then number is also divisible by 85.
Divisibility rule of 5 :
The last digit is 0 or 5, then number is also divisible by 5.
Last digit of 28900 is 0, which is divisible by 5.
`:.` 28900 is divisible by 5.
Divisibility rule of 17 :
5 times the last digit and subtract it from the rest of the number.
If the answer is divisible by 17, then number is also divisible by 17.
(Apply this rule to the answer again if necessary)
`2890color{red}{0}=>2890 - color{red}{0} xx 5 = 2890 = 2890`
`289color{red}{0}=>289 - color{red}{0} xx 5 = 289 = 289`
`28color{red}{9}=>28 - color{red}{9} xx 5 = 28 -45 = -17`
Here -17 is divisible by 17.
`:.` 28900 is divisible by 17.
28900 is divisible by 5 and 17.
`:.` 28900 is divisible by 85.
3. Check whether 32555 is divisible by 85 or not?Solution:Divisibility rule of 85 :
If number is divisible by 5 and 17, then number is also divisible by 85.
Divisibility rule of 5 :
The last digit is 0 or 5, then number is also divisible by 5.
Last digit of 32555 is 5, which is divisible by 5.
`:.` 32555 is divisible by 5.
Divisibility rule of 17 :
5 times the last digit and subtract it from the rest of the number.
If the answer is divisible by 17, then number is also divisible by 17.
(Apply this rule to the answer again if necessary)
`3255color{red}{5}=>3255 - color{red}{5} xx 5 = 3255 -25 = 3230`
`323color{red}{0}=>323 - color{red}{0} xx 5 = 323 = 323`
`32color{red}{3}=>32 - color{red}{3} xx 5 = 32 -15 = 17`
Here 17 is divisible by 17.
`:.` 32555 is divisible by 17.
32555 is divisible by 5 and 17.
`:.` 32555 is divisible by 85.
4. Check whether 25221 is divisible by 85 or not?Solution:Divisibility rule of 85 :
If number is divisible by 5 and 17, then number is also divisible by 85.
Divisibility rule of 5 :
The last digit is 0 or 5, then number is also divisible by 5.
Last digit of 25221 is 1, which is not divisible by 5.
`:.` 25221 is not divisible by 5.
Hence 25221 is also not divisible by 85.
5. Check whether 25509 is divisible by 85 or not?Solution:Divisibility rule of 85 :
If number is divisible by 5 and 17, then number is also divisible by 85.
Divisibility rule of 5 :
The last digit is 0 or 5, then number is also divisible by 5.
Last digit of 25509 is 9, which is not divisible by 5.
`:.` 25509 is not divisible by 5.
Hence 25509 is also not divisible by 85.
6. Check whether 32376 is divisible by 85 or not?Solution:Divisibility rule of 85 :
If number is divisible by 5 and 17, then number is also divisible by 85.
Divisibility rule of 5 :
The last digit is 0 or 5, then number is also divisible by 5.
Last digit of 32376 is 6, which is not divisible by 5.
`:.` 32376 is not divisible by 5.
Hence 32376 is also not divisible by 85.
This material is intended as a summary. Use your textbook for detail explanation.
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