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The wages earned by Robin is 30% more than...

by BTGmoderatorLU » Tue Oct 24, 2017 4:19 pm
The wages earned by Robin is 30% more than that earned by Erica. The wages earned by Charles is 60% more than that earned by Erica. How much percent is the wages earned by Charles more than that earned by Robin?

A. 18.75%
B. 23%
C. 30%
D. 50%
E. 100%

The OA is B.

I need help with this PS question. Can any expert explain it please? Thanks.
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by DavidG@VeritasPrep » Wed Oct 25, 2017 6:59 am
LUANDATO wrote:The wages earned by Robin is 30% more than that earned by Erica. The wages earned by Charles is 60% more than that earned by Erica. How much percent is the wages earned by Charles more than that earned by Robin?

A. 18.75%
B. 23%
C. 30%
D. 50%
E. 100%

The OA is B.

I need help with this PS question. Can any expert explain it please? Thanks.
Let's say Erica earned $100.
If Robin earned 30% more than Erica, then Robin earned 130.
If Charles earned 60% more than Erica, then Charles earned 160

Effectively, we want to know the percent increase from 130 to 160; plug and chug into our trusty %-change formula: (New-Old)/Old * 100, and we get: (160-130)/130 * 100 = (30/130) * 100 =( 3/13) * 100. If 3/12 = 25%, then 3/13 will be a tad lower. The answer is B
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by ceilidh.erickson » Wed Oct 25, 2017 3:04 pm
LUANDATO wrote:The wages earned by Robin is 30% more than that earned by Erica. The wages earned by Charles is 60% more than that earned by Erica. How much percent is the wages earned by Charles more than that earned by Robin?

A. 18.75%
B. 23%
C. 30%
D. 50%
E. 100%

The OA is B.

I need help with this PS question. Can any expert explain it please? Thanks.
What is the source of this question? The wording is TERRIBLE!
- "The wages... is..." --> not grammatically correct
- "30% more" is not the GMAT-preferred idiom. "30% greater" is.
- "How much percent... more" is borderline nonsensical.

Furthermore, the actual answer to this question is not 23%. It's 23.076923....%
On a real GMAT problem, if the answer were approximate, the problem would use the word "approximately."

Studying from non-GMAT-like sources is a really bad idea. The content of this particular question is similar to what you'd see on the real test (though very easy). However, if whoever wrote this question knows this little about grammar and coherent meaning, I would really not trust this source to study from.

This is why it's important to ALWAYS POST YOUR SOURCES!
Ceilidh Erickson
EdM in Mind, Brain, and Education
Harvard Graduate School of Education
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by EconomistGMATTutor » Wed Oct 25, 2017 4:48 pm
The wages earned by Robin is 30% more than that earned by Erica. The wages earned by Charles is 60% more than that earned by Erica. How much percent is the wages earned by Charles more than that earned by Robin?

A. 18.75%
B. 23%
C. 30%
D. 50%
E. 100%

The OA is B.

I need help with this PS question. Can any expert explain it please? Thanks.
Hi LUANDATO,
Let's take a look at your question.

The question states:
The wages earned by Robin is 30% more than that earned by Erica.
Let Erica's earning = x
Then Robin's earning = x + (30%)x = x + (30/100) x = x +0.3 x = 1.3 x

Next the question states:
The wages earned by Charles is 60% more than that earned by Erica.
Charles earning = x + (60%)x = x + (60/100)x = x + 0.6x = 1.6x

We are asked to find the percent change of how much Charle's earning more than Robin's earning.
Percent Change = [(Charles Earning - Robin's Earning) / Robin's Earning] * 100%
Percent Change = [(1.6x - 1.3x) / 1.3x ] * 100%
Percent Change = [ 0.3x / 1.3x ] * 100%
Percent Change = (3/13) * 100%
Percent Change = (300 / 13) %
Percent Change = 23% approximately

Therefore, Option B is correct.

Hope it helps.
I am available if you'd like any follow up.
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by Jeff@TargetTestPrep » Sun Oct 29, 2017 6:26 am
LUANDATO wrote:The wages earned by Robin is 30% more than that earned by Erica. The wages earned by Charles is 60% more than that earned by Erica. How much percent is the wages earned by Charles more than that earned by Robin?

A. 18.75%
B. 23%
C. 30%
D. 50%
E. 100%
We can let Erica's wage = E, so Robin earns 1.3E and Charles earns 1.6E.

Now we can determine what percentage greater Charles's wages are than Robin's.

(1.6E - 1.3E)/1.3E x 100 = 0.3E/1.3E x 100 = 3/13 x 100 ≈ 23%.

Alternate Solution:

Let's assume that Erica earns 100 dollars. This means that Robin earns 130 dollars and Charles earns 160 dollars. We use the percent difference formula:

(Charles $ - Robin $)/Robin $ x 100:

(160 - 130)/130 x 100 = 30/130 x 100 = 3/13 x 100 ≈ 23%.

Answer: B

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