DS---Ratio

[hershpuri18885]

What is the ratio of r to s?

(1) r + s = 7

(2) r2 - s2 = 7

Why not 2?Or B ||The answer is C ...

[jnelson0612]

What is the ratio of r to s?

(1) r + s = 7

(2) r2 - s2 = 7

Why not 2?Or B ||The answer is C ...

Hi hershpuri,
Okay, so if the problem is asking us the ratio of r to s then mathematically it is asking what is r/s?

So r could be 4 and s could be 3. r/s is 4/3.

Or r could be -4 and s could be 3. r/s is -4/3.

Once we have two answers using a statement we have proven insufficiency.

This one is similar to the one that you asked Tim about. Whenever you have even exponents you have to consider that you can have a positive and a negative value for the variable.

Let us know if you need help with seeing how we can solve with both statements together.

[hershpuri18885]

Thanks Jamie !!!

[hershpuri18885]

i applied r2-s2= 7
(r+s)(r-s)=7
(4+3)(4-3)=7
7.1=7

let me try it with r=-4 and s=3
(-4+3)(-4-3)
(-1)(-7)
7=7

Thanks again...

[jlucero]

Are you asking a question here or just showing your work? Just to be clear, you wrote 7.1=7, when it should be 7*1=7, but since r=4, s=3 OR r=-4, s=3, the ratio of r/s could be 4/3 or -4/3, meaning it's insufficient.