Find the number of theater seats in an auditorium with 50 rows where the first row has 20 seats and each successive row has 2 more seats than the previous?
This forms an arithmetic progression:
Sum=N/2[2F + (N -1)*D]
Sum =50/2[2*20 + (50 -1)*2]
Sum =25[40 + 98]
Sum =25 x 138
Sum =3,450 - number of seats in the theater.
Find the number of theater seats in an auditorium with 50 rows where
the first row has 20 seats and
each successive row has 2 more seats than the previous?
Formula:
tn=t1+(n−1)⋅dsn=(t1+tn2)⋅n
n=50t1=20d=2t50=20+(50−1)⋅2t50=20+49⋅2t50=118s50=(20+1182)⋅50s50=(1382)⋅50s50=69⋅50s50=3450
The number of theater seats in an auditorium is 3450