Anaira Mitch wrote:In a two-month survey of shoppers, each shopper bought one of two brands of detergent, X or Y, in the first month and again bought one of these brands in the second month. In the survey, 90 percent of the shoppers who bought Brand X in the first month bought Brand X again in the second month, while 60 percent of the shoppers who bought Brand Y in the first month bought Brand Y again in the second month. What percent of the shoppers bought Brand Y in the second month?
(1) In the first month, 50 percent of the shoppers bought Brand X.
(2) The total number of shoppers surveyed was 5,000.
Statement 1:
Let the total number of shoppers in the first month = 100, implying
50 X-shoppers and
50 Y-shoppers.
Since 90% of the 50 shoppers in red repurchased X in the second month, the red group in the second month yields
45 X-shoppers and 5 Y-shoppers.
Since 60% of the 50 shoppers in blue repurchased Y in the second month, the blue group in the second month yields
30 Y-shoppers and 20 X-shoppers.
Thus:
(total Y-shoppers in the second month)/(total shoppers) = (
5 +
30)/100 = 35/100 = 35%.
SUFFICIENT.
Statement 2:
No information about the percentage of Y-shoppers in the second month.
INSUFFICIENT.
The correct answer is
A.
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