FDP Question Bank - Q12

[vak3e]

what is the mental checklist does an expert solver go through while solving problems like this? I understand that plugging in values is an option, but it's probably too time consuming for a complex problem such as this! I solved this by:

Picking a simplifying value -- like 50% for Y and z=0, and this helped eliminate all but 2 answer choices very quickly. However, this left me with a difficult guess and I just had to rely on intuition. The answer solution (below) says to pick different values, but it seems WAAYYY to time-consuming and error prone, especially if you have to do one plug. So in essence, I'm often left with the feeling that for 700-800 level problems of this time there's nothing to do but eliminate a few of the answer choices by picking simplifying values, and then rely on intuition. Expert opinion would be really helpful . Thank you!

Currently, y percent of the members on the finance committee are women and next month, z percent of the men on the finance committee will resign. If no other personnel changes occur, then after the resignations next month, the men who remain on the finance committee will represent what percent of the total finance committee members?



These are the answer choices, the lower expression in each one is the devisor.

(100)(100 - z)(100 - y)
100^2 - z(100 - y)

(100 - z)(100 - y)
100

(100 - z)(100 - y)

zy
100 - z

z(100 - y)
100


The answer is A
They recommend solving by:
In order to make this problem less abstract, we can pick values for each of the unknown variables in the problem.

Let's assume there are 100 individuals originally on the committee.
Let y = 60.
Let z = 25.

I'm not including the math. Thank you for your help guys!

[RonPurewal]

what is the mental checklist does an expert solver go through while solving problems like this?

This is not a question with a single answer. If you have N different "expert solvers", you're going to have at least N different ways of approaching the problem"”and probably more than N different ways.

If there were one characteristic common to "expert solvers", that characteristic would be flexibility"”i.e., NOT having a single "mental checklist". Just having lots and lots of different ways to approach the problem"”and being unhesitating, even reckless, about trying them.

[RonPurewal]

I understand that plugging in values is an option, but it's probably too time consuming for a complex problem such as this!

If you can't think of anything else, then you should just DO IT.

NEVER tell yourself "I think this will take too long".

NEVER talk yourself out of doing something that might actually work.

Never.

Put another way"”
What you're saying here is, in essence, "I might get lost if I try this method."
Well, okay. Do you have another method? If not, then pick up the shovel and dig.

Worst-case scenario, you can always just quit. But it's impossible to argue with the assertion that trying something is better than not trying something.

[RonPurewal]

The answer solution (below) says to pick different values, but it seems WAAYYY to time-consuming and error prone, especially if you have to do one plug.

I think you're overestimating the time required to plug in another set of numbers.

Once you've gone through the process once, plugging another set of numbers means executing exactly the same process again.
This will be MUCH faster than your initial execution of the process.

[vak3e]

I see! Makes sense, and I see your point about trying something ASAP and not sticking to one particular approach

[RonPurewal]

Excellent.