Question 46 Problem Solving 2018 GMAT Official Guide:

In this question: in the video explanation; when we take examples , 23+32 = 55, so 55 is also not divisible by 9 right, so in first example itself we eliminate answer options of 6,9,10,14 and left with 9.

In video it is mentioned that for 23+32= 55, we have two answer options , ie 9 and 11. Please advice. Thank you

Thanks for pointing out the error. Yes, the example of x=23 and y=32 would give you the correct answer because that number is only divisible by 11. I will make the correction.

Are you referring to the $10$ that I used in writing a two digit integer $tu$, where $t$ is the tens digit and $u$ is the units digit, and the value of the integer is equal to $10t+u$?

georg vilshofen says

Note this is labeled as #46 from OG 2018, though the video correctly covers #63 from 2019.

georg vilshofen says

OK, I see; it’s the same problem as in OG 2018, with a diff number.

Jayita Ghosh says

Question 46 Problem Solving 2018 GMAT Official Guide:

In this question: in the video explanation; when we take examples , 23+32 = 55, so 55 is also not divisible by 9 right, so in first example itself we eliminate answer options of 6,9,10,14 and left with 9.

In video it is mentioned that for 23+32= 55, we have two answer options , ie 9 and 11. Please advice. Thank you

GMAT Quantum says

Hi Jayita,

Thanks for pointing out the error. Yes, the example of x=23 and y=32 would give you the correct answer because that number is only divisible by 11. I will make the correction.

Dabral

ian says

Why did u take 10? Why not any number in the first approach. Please reply.

GMAT Quantum says

Are you referring to the $10$ that I used in writing a two digit integer $tu$, where $t$ is the tens digit and $u$ is the units digit, and the value of the integer is equal to $10t+u$?