Question

divisible by 3 or 7 between 1 to 50​

Answer 1

Step-by-step explanation:

3 and 5 are co-prime (share no factors), so only numbers divisible by the product of 3 and 5 (15) will work.

So count by 15’s until you hit your limit of 50 to get the numbers {15, 30, 45}.

Now, full disclosure: I actually wrote a silly Basic program to find these. When I saw the output, the reasoning I should have used became very, very clear.

I guess sometimes you just have to do things the hard way at least once. (smile)