In the addition table shown above, what is the value of m + n ?

Question

https://gmatclub.com/forum/download/file.php?id=68050 In the addition table shown above, what is the value of m + n ? A. -19 B. 4 C. 5 D. 6 E. 22 Untitled.png Untitled.png

Bunuel · Accepted Answer

https://gmatclub.com/forum/download/file.php?id=68050

In the addition table shown above, what is the value of m + n =?  
A. -19 
B. 4 
C. 5 
D. 6 
E. 22

The sum of some value from the first row and and some value from the first column is given in the intersection boxes of these values.

So:

x+4=1 ;
  x=-3 .

y+4=-5 ;
  y=-9 .

x+e=-3+e=7 ; 
  e=10 .

y+e=-9+10=n ; 
  n=1 .

z+e=z+10=10 ;
  z=0 .

z+4=0+4=m ;
  m=4 .

Therefore,  m+n=4+1=5 .

Answer: C.

KarishmaB · Answer

It will.

+ x y z
4 1 -5 m
e 7 n 10
f 2 -4 5

Take an aggressive approach. First find out what you want to know: m + n
m = 4 + z and n = e + y so you need  4 + z + e + y

Now, y is simple. 4 + y = -5 so y = -9
e and z are trickier. Looking at the 2nd column, if I have x, I can find e. 
x is simple. 4 + x = 1 so x = -3
Now, e + x = 7 which means e -3 = 7 so e = 10
Only z remains. e + z = 10 so 10 + z = 10 giving me z = 0
I have all I needed. 4 + z + e + y = 4 + 0 + 10 -9 = 5

manitshah · Answer

the simplest way to do this is through a series of successive substitutions.
whenever there's a () in the working below, it means i have substituted a value that i found in an earlier step.

cheers.

x + 4 = 1
therefore, x = -3

y + 4 = -5
therefore, y = -9

x + e = 7
(-3) + e = 7
therefore, e = 10

y + e = n
(-9) + (10) = n
therefore, n = 1 ...(i)

z + e = 10
z + (10) = 10
therefore, z = 0

z + 4 = m
(0) + 4 = m
therefore, m = 4 ...(ii)

using (i) and (ii), m + n = 5

Ans = 5

intcan · Answer

4 + z = m
e + y = n
e + z = 10
4 + y = -5
4 + z + e + y = m + n
m + n = 10 - 5 = 5

Spidy001 · Answer

On careful observation , this problem can be easily solved under 2 mins.

m +n = 4 +z + e +y = 4 +(z+e)+y = 4 +10+y = 14+y

solve y separately, y = -9 => m+n = 14-9 =5.

Answer is C.

MHIKER · Answer

How will I know that The sum of some value from the first row and and some value from the first column is given in the intersection box of these values. What is the mechanism?

KarishmaB · Answer

If you are not aware of the concept of 'addition table', the mechanism isn't intuitive. It might take some time to figure out. On the bright side, you now know the mechanism behind an addition table and if some other such concept does crop up in your actual GMAT, they will explain you how to arrive at the values. Very rarely will you see ambiguity in actual GMAT questions (If it does arise, they are quick to fix it.) So just know what this concept is and move on.

siddharthmuzumdar · Answer

This one is quite easy actually. I, frankly, do not think that this is 700-level. But then again, it is just my opinion.

Here is my explanation:

Question:  m + n = ?

Now  m = z + 4; n = y + e

Hence,  m + n = z + 4 + y + e = (z + e) + (y + 4)

If you observe the table again, you know that  (z + e) = 10  and  (y + 4) = -5 .

Add them to get  m + n = 5

Answer: C

mk0991 · Answer

Q # 2 on my GMAT Prep test # 1... :roll:

spent 5 minutes trying to figure it out and still couldn't. Now I am worrying more than ever about such ridiculous questions....

KarishmaB · Answer

You don't have to worry. If this question was a part of GMAT at some time, it was a very very long time back. GMAT has been evolving and now if they use a term such as 'addition table', they are not going to assume that you know what it is. They will explain you what an addition table is i.e. they will tell you something like this" "An addition table is where numbers in the first row get added to numbers in the first column to give the results given in the grid e.g. 4 + X = 1, E + Y = N etc."
The stats related to every question are monitored and if they see inconsistencies, they filter them out e.g. if they see people getting more than Q49 but sitting on this 500 - 600 level question for 5 mins, they will figure out why and take action. In GMAT, the intent of the question will be very clear. You will only have to worry about 'how to get the answer' not 'what do they want'.

PrashantPonde · Answer

addition table.jpg We do not have to calculate value of any variable here. The solution can be simplified as below: m=z+4 and n=y+e Hence m+n = z+4+y+e = (y+4) + (z+e) From yellow cell (y+4) = -5 From green cell (z+e) = 10 Substitute above in (m+n) equation m+n = (y+4)+(z+e) = -5+10= 5 Hence choice(C) is the answer.

GMATinsight · Answer

Answer: option C

Check solution as attached

Basshead · Answer

m + n = 4 + z + e + y

4 + y = -5

z + e = 10

10 + (-5) = 5

Answer is C.

TheAlchemist36 · Answer

10 years since this post was published and GMAC has decided to retain it on the GMAT prep mocks. It seems as though we must be prepared for such surprises.

bumpbot · Answer

Automated notice from GMAT Club BumpBot: 

A member just gave Kudos to this thread, showing it’s still useful. I’ve bumped it to the top so more people can benefit. Feel free to add your own questions or solutions.

 This post was generated automatically.

In the addition table shown above, what is the value of m + n ?

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards

GMAT Problem Solving (PS) Questions

In the addition table shown above, what is the value of m + n ?

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards