11. In an artistic event it is observed that the seats in a room have been placed in a total of 20 rows: 20 in the first, 24
in the second, 28 in the third, so on until the row
ten, and from the next row on they all have 30 seats.
Determine how much was raised if fully booked and charged
20 soles the entrance.
A) 18000 B) 22000 C) 24000 D) 26000 E) 28000