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Jonas99
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Strategy for: Solving for one variable in terms of the other 07 Sep 2024, 00:17
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­If r=s+a and r+s=b, what is is s in terms of a and b.

While this is indeed a rather simple example, I am looking for some guidance on strategies for how to solve this type of question:
- How do you decide which variable to subsititute for which variable / part of the other equation?

Many thanks!
Jonas
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Strategy for: Solving for one variable in terms of the other 07 Sep 2024, 00:35
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­If r=s+a and r+s=b, what is is s in terms of a and b.

While its good to have some common approaches to GMAT problem - it is best to not design one template for each question type from a category. Be open to different approaches and be more focused on question stem cause that visualisation skill will help you to bend a probelm to the intended result

What do we need to find? S ok

s = r - a
s = b - r

Once I did this I observed that if I added the equation I could eliminate r completely due to opposite signs

2s = b - a

S = (b-a)/2

Hope this helps.
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Strategy for: Solving for one variable in terms of the other 07 Sep 2024, 02:52
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Jonas99
­If r=s+a and r+s=b, what is is s in terms of a and b.

While this is indeed a rather simple example, I am looking for some guidance on strategies for how to solve this type of question:
- How do you decide which variable to subsititute for which variable / part of the other equation?

Many thanks!
Jonas
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­We have two equations:

r = s + a
r + s = b
We want to express s in terms of a and b. So, we need to eliminate r. One way is to express r in terms of the other variables in one equation and substitute it into the other:

From the first equation, we have r = s + a.

Substituting this into the second equation gives:

(s + a) + s = b
2s = b - a
s = (b - a)/2
Alternatively, we could subtract the second equation from the first, noticing that this also eliminates r:

r - (r + s) = (s + a) - b
-s = s + a - b
s = (b - a)/2

Check similar questions below:
Hope this helps.­
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Strategy for: Solving for one variable in terms of the other 11 Sep 2024, 02:43
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@Jonas99­If r=s+a and r+s=b, what is is s in terms of a and b.

r & s are variables whereas a & b are constants. We have to eliminate r & find s in terms of a & b.

r = s+a = b - s
2s = b - a
s = (b-a)/2

Hope it helps!
­
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