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, an = 994
an = 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