abhimahna wrote:
PedroBodnar wrote:
Could someone please tell me if my approach described below is valid?
I assume that I have 5 different variables (m, n, average, Kevin's score, Kathrerine's score) and only two equations.
Statement (1) gives me one more equation - INSUFF
Statement (2) gives me one more equation - INSUFF
Statement (1) & (2), combined, give me two more equation
Then I still have 5 different variables for 4 different equations, hence INSUFF
Does this approach makes sense?
Hey
PedroBodnar ,
Unfortunately, your approach isn't valid. You don't have any two separate values as Kevin's or Katherine's score. There are nothing but a relation of A and m/n.
We are given the Kevin's Score = A + m % of A (where A is class Average).
Similarly, Katherine's score = A + n % of A
Question is asking you to find out A.
Statement 1: n - m = 7 ==> You can't find out anything here.
Statement 2: m = 12 ==> No information about n or A.
Combining,
m = 12 => n - 12 = 7
or n = 19
Now, you have m and n but you don't have relationship between Katherine's and Kevin's score. Thus, you can't find out A. Hence, E.
Does that make sense?
I see.
I have spent some time trying to figure out if this approach will work in every case, and I concluded then it will not.
It has to do with what you mentioned.
If I have 5 variables and only 4 equations, but one equation gives me the relationship between two variables, then I might be able to solve it, like you mentioned in this case.
In other scenario, for instance, if I have to find n and I have the equations:
(1) n+x+y = 1
(2) x+y = 3
Even though I have only two equations for 3 variables, I'm still able to solve it.
Conclusion: In any given case that I have a n variables for m equations, I'll have to find out if:
1 - any of those equations are exactly the same (say, (1) x+y = 5 and (2) 2x+2y=10), or;
2 - any of those equations give me any relationship between variables that will allow me to eliminate two variables from one equation
Does this new approach makes sense?