If the price of a magazine is to be doubled, by what percent

(1) Clearly insufficient.

(2) Also insufficient without knowing the current price of the magazine. Because if the current price of the magazine is 1$, when doubled it'll become 2$, so increase is 4 times 0.25$ and decrease in the # of magazines sold will be 4*10=40% BUT if the current price of the magazine is 2$, when doubled it'll become 4$, so increase is 8 times 0.25$ and decrease in the # of magazines sold will be 8*10=80%.

(1)+(2) We know the current price and the relationship between the increase in price and decrease in the # of the magazines sold. Sufficient.

Answer: C.

Hope it's clear.
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C

1) price of mgz=$1
new price will be =$2

we do not know how much percent decrease will happen
insuff

2) we do not know the price of magazine
but for $0.25 rise 10% subscription reduces
insuff

1 and 2
u
suff

Clear C.. when two variables are interdependent , we generally require the values of both the variables to know the exact impact on each other , but impact on % change can be determined by % increase of % decrease of one variable as per the given details of the problme

I didnt understand the explanation for statement 2..can somebody pls help explain in simpler terms..

Thanks in advance!

the price of the mag is x

if it becomes 2x how much will it decrease

2x-x =n times .25

now we dont know x the statement 1 gives the value of x and help solve the problem

Hey guys,
why cant the answer be A?
My solution
Price x number = New Price X (number - y) where y represnts the decrease in the number of magazines after new rate.

So if price is 1 then new price would be 2
therefore, 1 x n= 2 x (n-y)
or (n-y)/ n= 1/2
n-y/ n is nothing but change from old to new divided by old (% age change) and 1/2 would represent 50%. So, by this method A should be sufficient.

Am I missing something?

This relationship implies that the price of the magazine is inversely proportional to the no of magazines sold. Such a relationship is not implied anywhere in F.S 1 or in the question stem.Thus, A is insufficient.
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The answer is straightforward here. The question stem is asking for the percentage difference in the sales of magazines due to the increase in price. To calculate the percentage difference in the no. of sales of magazines due to the increse in price, we require two parameters. Current Price and impact on sales due to the fluctuation in price.

1. It gives the information about only one parameter, Current price - Not sufficient
2. It brings more light into the direct relationship b/w changes in price and no. of magazines sold. - Not sufficient

1+2 -> We know the current price and also have the information about the decrese isn sales due to an increase in the price. Hence, sufficient.

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