Find the number of integers

Find the number of integers from 1 to 10,000 which are divisible by either 13 or 51
regards
Sridhar

Hello yshridhar

Welcome to Math Help Forum!

Quote:

Originally Posted by yshridhar

Find the number of integers from 1 to 10,000 which are divisible by either 13 or 51
regards
Sridhar

$10,000\div13 = 769.1$ , so there are $769$ integers from $1$ to $10,000$ that are divisible by $13$ .

In the same way, you can find the number of integers that are divisible by $51$ .

Add this number to $769$ . Then you will need to subtract the number of integers that are divisible by $13\times51\; (= 663)$ , because they will have been counted twice. (Note that $51 = 3 \times 17$ , so $51$ and $13$ have no common factors.)

Can you complete this now?

Grandad

Thank you Grandad
regards
Sridhar