How many three digit numbers are divisible by 7?

Let, three digit number divisible by 7 are

105, 112, 119,….994

Here, First term, a = 105

Common difference, d = 112 – 105 = 7

And last term, a_n = 994

a_n = a+ (n – 1) d

994 = 105 + (n – 1) 7

994 = 105 + 7n – 7

994 = 98 + 7n

7n = 896

n = 128

Hence, three digit number that are divisible by 7 are 128