Quickest Method Decision on PS/DS

[mohsinhassan14]

What are particular scenarios/strategies in which Plugging Values or Standard Algebraic method or Back solving will be quickest? How to decide between these method on planning phase of solving the question on DS or PS? Are there any clues in question which can give us clue to decide between these methods?

[messi10]

There are a couple of videos that Ron has done (Thursdays with Ron) on topics where algebra is not your friend. You should watch these.

If you do the questions in the OG and use the OG Archer, there are video explanations and answer explanations that discusses different ways to solve the same questions.

In my opinion, I don't believe that there are fixed rules that you can follow in terms of strategy. The more you practice and review, the more you will gain intuition. It also depends on your own ability of handling particular question types. For example, you may be good at using algebra a lot so you may find it easy to work with in most cases. On the other hand, you may not be that quick in which case, using another strategy may serve you better.

Lastly, you should be able to abandon a particular approach if you feel that you are not going anywhere partway through the question and be ready to try another approach.

[mohsinhassan14]

Many Thanks Messi for you great recommendations and suggestions.
I will watch Rod's videos and will practice hard to develop my intitution while deciding quickest method.

Thanks

Regards,

Mohsin Hassan

[StaceyKoprince]

messi10, great answer! I concur.

I'll elaborate on one thing. Mohsin, part of your study task is to figure out when it's better for you to use one method over the other. I'll give you some general guidelines, but anytime you run across problems like these in practice, try them BOTH ways (not in 2 minutes - try the problem twice!).

When you're done, ask yourself, "Okay, for *this* problem, which way was better? WHY? What was the structure of the problem or what were the other clues that could have told me, in hindsight, that it'd be better to pick numbers or it'd be better to do algebra?"

As a very general rule:
the easier the algebra (for you), the more likely you are to do the algebra

the harder the algebra (for you), the more likely you are to use one of the alternate methods

You're basically looking for the path of least resistance to the correct answer. :)

If the answer choices are "easy" numbers (integers that aren't too large, or are "rounded off" in some way, like 10, 15, 20), then maybe using the answers is easier than doing algebra.

If the problem and answers don't contain a real value for anything (that is, everything is in terms of variables, or percentages, or fractions of some unknown), then I can pick my own number(s). Should I? Depends how annoying the algebra is. The more annoying it is, the more I'd prefer to pick real numbers.

If the problem is a "theory" problem (no real numbers plus they're asking for some kind of characteristic, eg, is x odd?), then I may need to "test cases" (especially on data sufficiency or on must be true questions). I might have to try 2 or 3 different sets of numbers (that fit the given criteria) in order to narrow down to one answer.

Alternatively, I can use pure theory - which is often faster but only if you know the theory backwards and forewards. Otherwise, the theory will backfire. Here's one of those theory ones:
https://www.manhattangmat.com/blog/inde ... on-hiding/

There are lots of other articles like that on our blog, so also check those out!

Note: you have to learn how to use the "alternative" methods (plugging in the answers, picking your own smart numbers, testing cases) REALLY well. Otherwise, you're going to keep doing too-hard algebra because you don't feel comfortable enough with the alternative methods - and I'll tell you right now, the alternative methods are how most 99th percentile testers actually get those scores. :)

Good luck!

[mohsinhassan14]

Thank you do much Stacey for your great suggestions, tips and pearls of wisdom for me. This would be great help for me to boost my score. I would try to figure out every possible quickest alternative methods for each problem I solve. I will analyse the problem to the death.

Thank you so much

Regards,

Mohsin Hassan

[StaceyKoprince]

good luck! Let us know how it goes!