Number Properties Guide : Pg no. 169 Medium Practice : Q8

[xerocoool]

Hi,

Could you please explain how to go about solving this particular problem.

Q) Suppose each integer in the line segment 5<x<10 is divided into thirds with a dark gray tick mark at each third (1/3), and each integer is divided into ninths with a light gray line at each ninth (1/9). At how many places will a dark tick mark and a light gray line overlap ?

Thanks,
-X

[tommywallach]

Hey Xero,

Thanks for separating these. Be careful though, because you got the page number wrong (I've corrected the title), and you also copied down the question wrong. There's no variable in this question. It's just a line stretching between 5 and 10.

All we need to know is that every "thirds" mark will overlap with a "ninths" mark, because:

1/3 = 3/9
2/3 = 6/9
3/3 = 9/9

So all we need to know is how many thirds there are. Let's list 'em out!

5.333...
5.666...
6
6.333...
6.666...
7
7.333...
7.666...
8
8.333...
8.666...
9
9.333...
9.666...

That's 14 of them!

[kpkanupriyakhmi]

Can you please elaborate more on this Q? I didn't get the explanation and are the decimals difficult to handle o the gre?

[tommywallach]

Hey Kp,

My explanation is complete. There's nothing more to add. I also don't understand your second question.

-t