What is the ratio in which a dealer mixes two varieties of coffee?

Hi Prashant,

The Second statement says that The mixture is sold at 198/kg It does not tell how much it costs after mixing two varieties of coffee. The dealer might be earning some profit that's why cost price might differ from selling price. So, we can't form this equation 180x+210y=198z by combining both statements.

Detailed Solution
Let's say the ratio of two varieties is x:y

Statement 1: 180x+210y-- it does not tell anything further. So, this statement is not sufficient

Statement: It does not talk about the cost price. Just by knowing the selling price, we can't determine the ratio of two varieties of coffee.

Combining both statements:

Since the second statement does not tell any information relevant to first statement i.e. by knowing the cost price of two different varieties which dealer mixes and by knowing the selling price of the mixture, the ratio of two varieties can not be determined.

The correct answer is E.

Hope it helps.

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This is how I went with this question,
180x+210y=198z. x+y=z
By putting this value in the first equation.
x/y = 2/3. Answer is C. This is what the question has asked to calculate.

Good one !! I think you got most people over there with the nuance in statement - 2.
Only wondering if the GMAT will also tease us in the same way

E:
Statement II only gives the the selling price and not profit or Loss%.

Let say ,the dealer mixes 'x' kg coffee of price 180 per kg with 'y' kg coffee of price 210 per kg and makes total 'z' kg coffee of selling price 198 per kg.It means x+y=z (weight) .............According the question,180x+210y=198z (price). I need not consider profit or loss or how much coffee did the dealer sell because the question does not tell or ask anything about these. From weight equation and price equation,i get x=2 kg,y=3 kg and z=5 kg.So we can say,1. The dealer mixes 2kg coffee priced at 180 per kg with the 3kg coffee priced at 210 per kg

2. The mixture of coffee is 5kg and sold at 198 per kg.
That means ,the ratio in which a dealer mixes two varieties of coffee is 2/3.

There is a ridiculous twist in the question from which official questions will always refrain. It seems like the 2nd statement is actually made to trick people into thinking that the price is the final price. Not a cool question!!
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If the Second statement was stated as 'The cost of mixture is 198/kg' then could we determine ratios ?