Seats unoccupied

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Seats unoccupied

by Mario_87 » Sun Jun 30, 2013 7:34 am
How many seats in a theatre are unoccupied?

(1) There are an average of 3.5 unoccupied seats per row
(2) The theatre has more than 9 and fewer than 12 rows

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by srcc25anu » Sun Jun 30, 2013 5:02 pm
St1: Avg unoccupied seats per row = 3.5
We don't know the number of rows so cant determine the # of unoccupied seats
Insufficient

St2: More than 9 rows and fewer than 12 rows
so it could have either 10 or 11 rows
Insufficient

Together 1 + 2: We can only have 10 rows since 10 * 3.5 = 35 unoccupied seats
It cannot be 11 rows since that will yield a non-integer number of unoccupied seats and that is not possible.
No of seats should always be an integer.
Hence Sufficient
Ans C

What's the OA?