VICs question (percent)

[iil-london]

[Problem deleted because it is from a banned source. Please read (and follow!) the forum guidelines. Thanks!]

How can I solve this using the VICs technique described in the strategy guide ?
I tried substituting numbers ... and got (A) or (E) ... tried another set of number ... and this also left me with (A) or (E).

Also what would be an alternative approach to solve this question ?

Thanks.

[Sudhan]

Rephrase the question as

x= m (y)/100----------------(1)

So the question is asking us to find

y= x%(m)

From (1), we can rearrange as,
y= 100x/m-----------(2)

Since the question asked about Percentage.
multiply by 100 on the RHS in (2)
y= 100*100/m (x)
= 10000/m (x)

Hence E

Hope it helps

[RonPurewal]

you need to post a source for this problem. please do so in the next couple of days, or else we'll have to delete the thread.

thank you.

[iil-london]

Hi Ron,

This was from the OG 11 Guide.

[Guest]

Rephrase the question as

x= m (y)/100----------------(1)

So the question is asking us to find

y= x%(m)

From (1), we can rearrange as,
y= 100x/m-----------(2)

Since the question asked about Percentage.
multiply by 100 on the RHS in (2)
y= 100*100/m (x)
= 10000/m (x)

Hence E

Hope it helps

Thanks Sudan ... I understand this approach ... I also managed to solve this algebraically ...

However, I was stuggling with this question when trying to use the VICs approach described in the MGMAT EIV strategy guide and trying to plug in numbers.
Anyone have any comments on that ?

Thanks.

[iil-london]

I got it ... with VICs when you plug in numbers, you have to be careful with the numbers you use !

Initially, I used the following numbers:

x = 5
m = 10
y = 50

x is m percent of y
5 is 10 percent of 50.

y is what percent of x -> 50 is what percent of 5 -> 50 is ((50/5)*100) 1000 percent of 5.
So our target number is 1000.
However, when running through the answer choices both answer choices A and E reveal the target number (1000).

(A) 100m => 100 * 10 => 1000
(E) 10000/m => 10000/10 => 1000

So we have to try other numbers:

Let x = 15, m = 25, and y = 60 -> (15 is 25% of 60)
60 is 400% of 15. So our target number in this case is 400.

Which one of A or E will give us the target number? Lets try:

(A) 100m => 100*25 => 2500
(E) 10000/m => 10000/25 => 400

So E is the correct answer.

My question to the instructors (or anybody else) is what is the best way to find the smart numbers, so as to avoid going through a second iteration of plugging numbers through the answer choices.
And all this takes TIME ! Of which we have a very limited amount in the GMAT.

Any tips or best practices on how to quickly make a decision on the approach to take for a particular problem (VICs plugging numbers V algebraic) ?

Thanks in advance.

[Sudhan]

I think numbers such as 100, 50 will be easy to solve when we get Percentage related questions. We can use VIC method to solve the problem but considering the time factor, we need to get it done less than 2 minutes.

Thanks

[Guest]

As you pointed out it is possible to pick numbers such that two answers equal the target. This seems to happen when one picked number is a multiple of another.
Should try and go for prime numbers. With primes, you don't run that risk.
Any other thoughts on this ?

[StaceyKoprince]

Hi, guys

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