A home owner must pick between paint A, which costs $6.00

Even i marked A as answer, but kaplan math workbook solution suggests E as answer.

I think we cannot assume area covered to be directly proportional to liters of paint.

Huh. Something is definitely fishy here. I'll make sure this gets passed along. Thanks for pointing this out!

Ian / Karishma

Your opinion on this one please? I think the first ratio is enough to answer the question

From statement 1
It is actually the ratio of quantity of paint A used : quantity of paint B used = 3:4

If a = quantity of paint A used
b = quantity of paint B used
t1 = time required to apply paint A
t2 = time required to apply paint B

We are given that t2 = 4/3 or t2 = 1.33t1

and

a = 3/4 b = 0.75 b

The question becomes is 6a + 36 t1 < 4.5b + 36 t2
Or 6 * 0.75b + 36t1 < 4.5b + 36 t2
4.5b + 36t1 < 4.5b + 36t2

or The question becomes - Is t1 < t2 ?
We know that this is true. Sufficient

From statement 2

We don't know the quantity of paint B used. Insufficient.

Answer A

First, I think it's a ridiculous question, because most people would (very reasonably) assume that one liter of paint A covers the same area as one liter of paint B. According to Statement 1, that's not the case. Second, with Statement 1 alone, we can answer the question: if we need 4 liters of paint B to cover the same area as 3 liters of paint A, then it will cost 4(4.50) = 18 dollars to cover that area with paint B, and 3(6) = 18 dollars to cover that area with paint A. So the paint costs are the same; the total cost will only be different because of labor costs. Since paint B takes longer to apply, paint B will cost more to apply, and Statement 1 is sufficient.

I have no idea how they can give E as an answer here, since if you use both Statements, you can work out exactly how many liters of each paint you'd need and how many hours each paint would take to apply.

Kaplan workbook says E is the answer. I got confused with the wording of this question too. Any thoughts on what score scale would be for this question (400-500, 600-700, 700+)? For me, I try to keep in mind how to calculate total price. Whenever I see a problems that have "cost per unit" I consider the "total cost = rate x time formula". If I need to compare total cost between paint A and paint B, one of the answer options should give me the time it takes for paint A to complete a task and the time it takes B to complete that same task. Or I should have the total cost but that's what the question is asking. In answer 1, I only get a ratio (remember ratios don't tell you how much the actual area is, which could help) and no time therefore insufficient. Answer 2, gives you how many liters A takes and number of hours. You don't know how many liters you need to complete the area for B though, this answer is insufficient. I think the confusing part of this question is the "1/3 longer to apply than paint A". Could it be that applying paint B can just take 1/3 longer but the total labor B takes is still uncertain? Hopefully this is a higher score question because I would just guess and move on. If it takes over 2 minutes to solve, you've gotten too many possible solutions, and you don't clearly have all your variables in the "total cost = rate x time formula" it's probably E. GMAT guru's feel free to chime in again on this one.

This is a poor quality question, so I wouldn't worry about it much.

Check Ian Stewart's comment: a-home-owner-must-pick-between-paint-a-which-costs-82605.html#p912827