I was able to get a value for m:

1+(-5)+m=4
-4+m=4
m=8

But could not solve for n. Could someone please show me how to get n?

Thanks.

Hi Anand,

interesting problem ;-)

the question is asking for m+n, from the matrix, you can see that m = z +4 and n = e + y. Also, from the matrix, z+e = 10 and 4+y = -5, hence m+n = 10-5 = 5.

-Raj.

It makes sense now.Thanks Raj!!!

yeah.

remember that the best thing you can do is think of a fast opener for problems like this.

there are additions in the table that will give you the values of the variables - such as the ones mentioned by poster 'raj' - and there are other additions that won't, but you don't want to agonize for too long over which ones are the right ones.
instead, you can just write a different equation for every cell in the table, in some sort of systematic order, and then just look at the equations and see which ones will give you actual values.

for instance, going down the left hand column, you can write the following equations:
4 + x = 1
e + x = 7
f + x = 2
only the first of these gives a value right away, but, once you've got that value, you can plug it into the other two and find the other values.

same deal for the other columns - just fire away. extensive forethought is your mortal enemy on a test with as much time pressure as this one.