Question

how many three digit numbers are divisible by 7 answer for this in the condition of arithmetic progression

Answer 1

The greatest 3-digit number divisible by 7 is 994.

Therefore the three-digit numbers are 105, 112, 119, 126,…………..994.

This is an Arithmetic progression with first term a=105, common difference d = 7, last term = 994. Hence there are 128 three-digit numbers divisible by 7

Answer 2

Answer:

There are two types of number divisible by 7 one is positive and another is negative . Negative 3 digit number are from -994 to -105 .

And positive number are from 994 to 105 . Therefore according to AP the formula is

Tn=a+(n-1)d

994=105+(n-1)7

127=(n-1)

n=128

But this is only for positive number .

There will be same 3 digit number divisible by 7 which is = 128 .

Therefore the answer is = 128 +128

=256

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