Question

How many integers from 100 to 999 are divisible by 7

Answer 1

I think Answer is 104.

Hope it's help you

Answer 2

The first and last three-digit numbers divisible by 7 are 105 and 994.

using arithmetic progression to calculate the number of integers from 100 and 999 are divisible by 7.

Using $a_n$ formula,

$a_n=a+(n-1)d$

Where $a_n=994, a=105, d=7$

Substitute the values,

$994=105+(n-1)7\\994-105=(n-1)7\\889=(n-1)7\\\frac{894}{7}=n-1\\127=n-1\\n=128$