Equations

[shobha.r.iyer]

+ X Y Z
4 1 -5 m
e 5 n 10
f 2 -4 5

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

A) 22
B) 11
C) 5
D) 6
E) 19

[welcome]

4+x = 1 => x=-3 ----2nd Row
e+x=5 => e+(-3)=5 => e=8 ----3rd Row
e+z=10=> 8+z=10 => z=2 ---3rd Row

4+z=m => 4+2 =6=z. ---1st Row

Oooop Forgot n .

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

e+y =n => n => -1

so m+n = 6-1 = 5.

Answer is 5.

[logitech]

m+n = (4+z) +(e+y) Little trick! - Re-arrange
= (4+y) + (e+Z)
= (-5) + ( 10)
= 5

[shobha.r.iyer]

m+n = (4+z) +(e+y) Little trick! - Re-arrange
= (4+y) + (e+Z)
= (-5) + ( 10)
= 5

Hi Logitech

could not understand the rearrangement
can you please explain in some details...

[shobha.r.iyer]

m+n = (4+z) +(e+y) Little trick! - Re-arrange
= (4+y) + (e+Z)
= (-5) + ( 10)
= 5

The answer 5 is right

[logitech]

m+n = (4+z) +(e+y) Little trick! - Re-arrange
= (4+y) + (e+Z)
= (-5) + ( 10)
= 5

The answer 5 is right

a+b+c+d = a+d+b+c

we know what m+n is equal to:

4+z+e+y

so try to find in the table whether you can use any of the pairs, since

4+y is defined as -5 use it
and since you are left with e+z use it too.

The guy who designed this question wanted us to see this so it is not a coincidence . If you see a question like that in the future you will understand what I mean.

[shobha.r.iyer]

m+n = (4+z) +(e+y) Little trick! - Re-arrange
= (4+y) + (e+Z)
= (-5) + ( 10)
= 5

The answer 5 is right

a+b+c+d = a+d+b+c

we know what m+n is equal to:

4+z+e+y

so try to find in the table whether you can use any of the pairs, since

4+y is defined as -5 use it
and since you are left with e+z use it too.

The guy who designed this question wanted us to see this so it is not a coincidence . If you see a question like that in the future you will understand what I mean.

thanks logitech

[shobha.r.iyer]

m+n = (4+z) +(e+y) Little trick! - Re-arrange
= (4+y) + (e+Z)
= (-5) + ( 10)
= 5

The answer 5 is right

a+b+c+d = a+d+b+c

we know what m+n is equal to:

4+z+e+y

so try to find in the table whether you can use any of the pairs, since

4+y is defined as -5 use it
and since you are left with e+z use it too.

The guy who designed this question wanted us to see this so it is not a coincidence . If you see a question like that in the future you will understand what I mean.

thanks logitech

i was solving this question as three equations with 4 variables

[kanha81]

m+n = (4+z) +(e+y) Little trick! - Re-arrange
= (4+y) + (e+Z)
= (-5) + ( 10)
= 5

Brilliant! Thanks.