Question

Numbers between 400 to 700 either divisble by 9 or 11

Answer 1

Let’s find LCM (least common multiple) of 72 and 88 to see the least number which is divisible by both 88 and 72.

Firstly we should take a look at prime factorization of 88 and 72:

88=2*2*2*11;

72=2*2*2*3*3;

Now we can say that LCM(88,72)=2*2*2*3*3*11=792.

As we can see only 792 belongs to [400, 800] interval, it’s the least and the last number for this interval.

So we have an answer: only 1 number between 400 and 800 is divisible by both 88 and 72.

Answer 2

Thank you for asking this question:

We will assume as the least no divisible by 9 is 405

And the most is 693

So AP will be formed

405,414,423..........................693

The formula for nth term is given by:

an=a+(n-1)d

So, 693=405+(n-1)9

288=(n-1)9

32=n-1

So, n=33

If there is any confusion please leave a comment below.