Could you explain how this fit in the context of GMAT?

This is an addition table, and the problem is from the GMATPrep software.

According to the table, 4+X = 1 and 4+Y=-5, which means X=-3 and Y=-9

E+X = 7, and X=-3, so E-3 = 7, or E=10.

E+Y = n ---> 10 + -9 = n ---> n=1

E+Z = 10 ---> 10+Z = 10 ---> Z=0

4+Z = m ---> 4+0 = m ---> m = 4

Since m=4 and n=1, we can finally get the answer:

[spoiler]m+n = 5[/spoiler]

thks indeed

uwhusky wrote:Could you explain how this fit in the context of GMAT?

yes i this is gmac prep software question
i was also stumped in this question
reason
i have not seen/done such type of problem in school

matrix table....

i have made such table during word problems,
but in such case ,we work as
the number should satisfy both horizontal way and vertical way
ie
a b tot
1 3 4
2 4 6
3.....

now if we think this problem in that way ,it tends to be very difficult and may go beyond 2 minutes....
so i just gave it up and made a guess....not an educated one but wild guess

some questions,
it is taught under which tropic?
how do know it is addition table,why not substraction table or multipication table
can any body bring the correct figure(so that we can plug in values in check ,why above method was difficult)

thanks for asking this question
i was planning to ask as well