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GMATPill Explanation
OK, so you know the rule: Total Number * Percentage = Actual Number
The question is asking “what is the total amount the salesman was paid.”—this means you need the dollar amount.

At a quick glance, you can see that (1) gives you a PERCENTAGE and (2) gives you a NUMBER.

So right off the bat, I am leaning towards (B) as the answer. But let’s make sure.

(2) tells us the salesman’s sales last week was $5,000. So how much did he make? Well, since he gets paid a fixed amount of $300 + commission%*(TotalSales – $1,000), you can easily calculate how much he gets paid since you now know the TotalSales from (2).
So that confirms (2) is good.

What about (1)?
Well, (1) is a percentage, so we don’t know if it’s good. The framework does NOT tell us that (1) is automatically no good. It just tells us that (2) is almost definitely correct.

So how do we go about evaluating (1)? Well, first take the information from the question stem and right down what you know.

You know the amount he was paid = $300 + .05(excess over $1,000) = $300 +.05(TotalSales-$1,000)

Now read (1). (1) says the amount he was paid = 10% of TotalSales.

Look at that! 1 Equation and 1 Unknown–which means this has a solution. Of course, don’t spend the time to solve this equation. But right away, you know you have enough information to find how much the guy was paid.

So (1) here is good as well.

In this case, both (1) and (2) are good.

Remember, when using this framework, you should be going through this thought process:

1) Since statement (2) has a number, it has a pretty high probability of being good.
2) Check to make sure that (2) makes sense—it does, so (2) is good.
3) Since statement (1) is a percentage, it has a pretty high probability of not being good, but not necessarily.
4) Write out any equations you know and see if you can somehow match things up
5) In this case, it turns out you can create a 1 equation/1 unknown scenario so statement (1) is also good.

SInce (1) and (2) are both good by themself, then you choose (D) as your final answer.

And yes, you should always write out equations that involve a few moving parts.

To further clarify, the only reason why (1) in OG #77 is good even though it is a PERCENTAGE, is because:

the info in (1) is a PERCENTAGE of a variable that was previously mentioned in the question stem.

In particular, (1) tells us the “10% of the amount of sales last week”

This percentage is previously referenced in the question stem:
“commission equals to 5 percent of the amount of his sales last week”

Do you see that? It’s a percentage of a variable that was previously mentioned.

Now compare OG#77 to the example in the video. The example in the video does NOT reference a variable previously mentioned in the question stem.

In the video, statement (2) says:
“The brokerage firm’s commission decreased the profit earned on the trade by 10%”
Ask yourself: Was “profit earned on the trade” a variable in the question stem?
Nope!

So it’s safe to assume that this question is “normal” and you can confidently move forward with the framework quickly.

So in the future, be aware of when the percentage they give references a variable previously mentioned in the question stem. In these cases, you should double check and ask yourself if things make sense.

For many students, the GMATPill explanation works a lot better.

More GMAT Questions

What is this GMAT question testing?

This question throws in singular vs. plural, some idiomatic phrases, and “it” references.

See if you can spot the pitfalls in this question and arrive at the correct one in as little time as you can.

Do you say:
“agreement prohibiting”
or do you say:
“agreement that would prohibit” ??

Or is either one ok? Watch the video above to find out!

How To Think Through This GMAT Prep Software Question

Go ahead and check out the GMAT Pill video explanation of this Official Guide Question.

This one provides information that is “%” and “%”….and then the question is asking about “%”. So in this case, it’s not about %’s and #’s. This one is entirely about %s. The above framework doesn’t let you speed through this one. Here is the question and a few pointers to speed thru:

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GMATPill Explanation
Recognize this question is asking you whether it’s possible to compare 1999 to 1997. Let’s see if we can by figuring out what they gave us first.

1998 = 1997(1+x/100)
1999 = 1998(1-y/100)

Be careful in laying this information out. You may have an inclination to say 1998= 1997 (1+x) but you need the divide by 100 because if you read the question carefully, it’s saying x percent. To convert to algebra terms you need the divide by 100. If you don’t, then the expression (1+x) might read (1+5)..and that would translate to 600% rather than the 1+5% = 1.05 that you are trying to use. So this is an important point. Divide by 100 in your expressions.

By substituting 1998 into the second equation we can get:
1999 = 1997(1+x/100)*(1-y/100)

So at least we know from the information they gave us, that we can compare 1997 to 1999. The problem is that it’s not yet solvable because it’s one equation with 2 unknowns.

Let’s check (1). We have x>y. Well, our equation above will become:
1999 = 1997 * (1+x/100-y/100-xy/10000)
Since x>y, we know that x-y>0…which is the same as x/100 – y/100 > 0. Great. That means:
1999 = 1997 * (1 + something positive – xy/10000). Still not enough info to solve since the unknown “xy” is still remaining.

Now we look at (2).
Going back to 1999 = 1997 *(1+x/100-y/100-xy/10000)
Using (2), we can get 0 This looks almost similar, but we can manipulate it. Since the left side is 0, just divide both sides by 100.

You get: 0/100 < x/100 – y/100 – xy/10000
or 0 < x/100 – y/100 – xy/10000
Going back to 1999 = 1997 *(1+x/100-y/100-xy/10000)
we can see that this is 1999 = 1997 * (1+ something greater than 0).
The equation is solved. (2) gets the answer so it’s B.

For many students, the GMATPill explanation works a lot better.