please don’t say that

(1/3*1/7)x=x/21, so, x=21 or multiple of 21.

What are you not getting in this explanation ?

doesn’t 1/3 of the apartment means 1/3 x total apartment

like shouldn’t the equation be 1/3 x total apartment + 1/7 x 1/3 x total apartment ?

The question is talking about `2 bed room apartment `

in both the cases . Let say for eg if you had 100 apartment and 1/2 of them were 2 bedroom that will give 50 and if 1/5 of those 50 two-bedroom apartment are front facing so you will do 50/5 = **10 (two bedroom + front facing)** or what you do instead is \frac{1}{2}\times \frac{1}{5}\times 100=10 (two bedroom + front facing).

Now, read the question it’s asking **could be** and not must be and also look at answer choices (all are integers) thus, whatever answer you get has to be an integer too. Also, as we didn’t initially know the quantity of the apartments we are assuming a variable for it let say `X`

and then you can follow the same process as in above example to get the answer

isn’t it asking for the total number of apartment instead of frontfacing-two apartment ?

Sorry , I could’ve have better framed it as both the **1/3 and 1/7 cases** we are talking about `two-bedroom apartment`

. If you still having problem then choose any number (let say 100) and then try to work the logic! Write it in paper so you understand it better!

okk, let me try