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
Seats unoccupied
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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?
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?