Question

1) There is an auditorium with 25 rows of seats. There are 10 seats in the first row, 12 in the second row, 14 seats in the third row and so on. Find the number of seats in the 20 row and also find how many total total seats are there in the auditorium?​

Answer 1

Answer:

There are 58 total seats in auditorium .

Step-by-step explanation:

Given , first row=10, second row=12,third row=14 and so on.

10,12,14,16 this an A.P.

a=10             d=12-10=2

aₙ=a+(n-1)d

a₂₀=10+(20-1)2

a₂₀=10+(19)2

a₂₀=10+38

a₂₀=48

There would be 48 seats in 20th row.

a₂₅=a+(n-1)d

a₂₅=10+(25-1)2

a₂₅=10+(24)2

a₂₅=10+48

a₂₅=58

∴Total seats are 58 in the auditorium.