Question

How many natural number between 100 and 500 are divisible by 3​

Answer 1

Answer:

Inclusive of 100 and 500, we have 401 numbers with which to work. First, divide 401 by 3 to answer the first part of the question. The result should be rounded down because, if there is a remainder, that means there is not another multiple of 3. So this division, in this way, gives us 133. Now, do the same thing with 7. 401/7 = 57. 133 + 57 = 190.

But multiples of 21 are counted twice, so they must be subtracted out once to get the true answer .

190-(500/21) = 190 - 24 = 166.

There are 166 numbers divisible by only 3, only 7, and 3 and 7 from 100 to 500.