How many three-digit natural numbers are divisible by 7?

1.	How many three-digit natural numbers are divisible by 7?
Answer» 3-digit natural numbers: 100, 101,…….. 990 and 3-digit natural numbers divisible by 7: 105, 112, 119, 126, …, 994 Here, a = 105, d= 7, l = 994 a_n = (l) = a + (n – 1) d 994 = 105 + (n – 1) x 7 994 – 105 = (n – 1) 7 n – 1 = 127 n = 128 Answer: There are 128 required numbers.

Answer»

3-digit natural numbers: 100, 101,…….. 990 and

3-digit natural numbers divisible by 7: 105, 112, 119, 126, …, 994

Here, a = 105, d= 7, l = 994

a_n = (l) = a + (n – 1) d

994 = 105 + (n – 1) x 7

994 – 105 = (n – 1) 7

n – 1 = 127

n = 128

Answer: There are 128 required numbers.

Discussion