Answer:
300
Explanation:
Change the fractions so that they have a common denominator.
2/3 = 4/6
1/2 = 3/6
The difference between 4/6 and 3/6 is 1/6. This is the number of people who left the concert (50) as the fractions changed after they left.
Since 4/6 - 3/6 = 1/6 which also = 50, the total number of seats, 6/6 = 50 × 6 = 300