To Find : 3 - digit numbers divisible by 7.

First 3 - digit number divisible by 7 is 105

Second 3 - digit number divisible by 7 is 112 and

Last 3 - digit number divisible by 7 is 994.

Given: The AP is 105, 112, 119,…………..,994

a₁ = 105, a₂ = 112, d = 112–105 = 7 and a_n = 994

(Where a=a₁ is First term, a₂ is Second term, a_n is nth term and d is common difference of given AP)

Formula Used: a_n = a + (n - 1)d

994 = 105 + (n - 1)7

889 = (n - 1)7

127 = (n - 1)

n = 128

So, There are total of 128 three - digit number which is divisible by 7.