Q11 of 105 Page 139

How many three-digit numbers are divisible by 7?

The series of three-digit numbers divisible 7 is,

105, 112, 119,…………. 994


So here first term (a) is 105


Since it is divisible by 7 the common difference will be 7


Let an = 994


an = a + (n-1) d


994 = 105 + (n-1) 7


889 = (n-1)7


127 = n-1


n = 128


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