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!$\displaystyle 10,000\div13 = 769.1$, so there are $\displaystyle 769$ integers from $\displaystyle 1$ to $\displaystyle 10,000$ that are divisible by $\displaystyle 13$.
In the same way, you can find the number of integers that are divisible by $\displaystyle 51$.
Add this number to $\displaystyle 769$. Then you will need to subtract the number of integers that are divisible by $\displaystyle 13\times51\; (= 663)$, because they will have been counted twice. (Note that $\displaystyle 51 = 3 \times 17$, so $\displaystyle 51$ and $\displaystyle 13$ have no common factors.)
Can you complete this now?
Grandad