At a certain convenience store, the revenue from Brand A hot dogs decreased by 5% from April to May, while the revenue from Brand B hot dogs increased by 5% from April to May. The revenue from Brand A in May was what percentage of the revenue from Brand B in April?

(1) The increase in revenue from Brand B was 19/20 the decrease in revenue from Brand A.

(2) The revenue in April from Brand A was equal to 20/19 the revenue in April from Brand B.
Choices

OA is A.

Could anyone please explain.

The OA is correct A. Since this does not seem more of math question I will try to use as much english as possible to explain DS. I also think the idea of this question is to make people enjoy scary maths over any other approach.

Q Says revenue from Brand A & Brand B share a percent decrease & increase during the accounting month of from April to May the statement underlined is very important. I will explain later why.

Now Question that need to be answered can we find the percentage revenue if statement 1 is given. YES. I do not want to focus on maths here however since all required information is presented we can caculate the revenue percentage (Revenue of Brand A/Revenue of Brand B * 100 ).

Statement 1 - The increase in revenue from Brand B was 19/20 the decrease in revenue from Brand A. Point to be noted here, the key thing about this statement is that it does not talk about the months and derives from the information above to provide revenue information. Hence Sufficient. We can setup the equation and solve.

Statement 2. The revenue in April from Brand A was equal to 20/19 the revenue in April from Brand B.
Choices.
Can I use the information in statement 2 ? NO. Why ? because it smartly introduces the month April

Now please revisit the question stem in the above bold letters :

Q Says revenue from Brand A & Brand B share a percent decrease & increase during the accounting month of from April to May the statement underlined is very important. I will explain later why.

Here is why :
1. Since the question is not asking us to calculate the revenue percentage itself for the month of April this information is insufficient or irrelevant to answer.
2. Since the revenue are given through the month of April to May we dont have the revenue information for the month of April and we cannot setup up the equations to solve this problem.

Please consider giving kudos if you like the explanation.
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Ros.
Nice Post + Some help + Lucid solution = Kudos

The greatest pleasure in life is doing what people say you cannot do | Great minds discuss ideas, average minds discuss events, small minds discuss people.
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Dude !!! If GMAT were an exam for math wizards only I would agree with your argument.

Since it is not, You need to use the presense of mind as well.

Can you please explain, considering you are correct what is the difference in Statement 1 and 2.

Assuming months can be ignored, it dosent matter if 19/20 or 20/19.

An an intelligent test taker it would be a waste of lot of energy and time to rewrite statement 1 in statement 2 with absolutely no change.

BEYOND ALL, Also consider this possibility April to May :

Could be 15 Apr - 15 May. If so, how would you know he revenue of accouting month from Apr to May at the end of APR?
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Ros.
Nice Post + Some help + Lucid solution = Kudos

The greatest pleasure in life is doing what people say you cannot do | Great minds discuss ideas, average minds discuss events, small minds discuss people.
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Given:

Q: \frac{0.95A}{B}=\frac{19A}{20B}=?

(1) The increase in revenue from Brand B was 19/20 the decrease in revenue from Brand A --> 0.05B=\frac{19}{20}0.05A --> \frac{A}{B}=\frac{20}{19} --> hence \frac{19A}{20B}=1. Sufficient.

(2) The revenue in April from Brand A was equal to 20/19 the revenue in April from Brand B --> A=\frac{20}{19}B --> hence \frac{19A}{20B}=1. Sufficient.

Answer: D.

Hope it's clear.
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