Question

There is an auditorium with 27 rows of seats. There are 20 seatsin the first row ,22 seats in the second row , 24 seats in the third row and so on . Find the number of seats in the 15th row and also find the total number of seats in the auditorium.
Can anybody solve this ???​

Answer 1

Answer:We have observed that the numbers of seats in each row increase in an AP

Thus in that AP, we have

=> a = 20

=> d = 22 - 20

=> d = 2

=> n = 27(total rows)

To Find : a15 and S27

For part 1, a15 = a + (n - 1)d

=> a15 = 20 + 14(2)

=> a15 = 20 + 28

=> a15 = 48

Thus there are 48 seats in the 15th row.

For part 2

S27 ⤵️

Replacing Values

Thus there are 1242 seats in the auditorium

Step-by-step explanation:

Answer 2

Step-by-step explanation:

in all the rows the seats are increasing by 2

so it will be=24+2+2+2+2+2+2+2+2+2+2+2+2

= 24+24

=50 seats are there in the 15th row

as there are 27 rows so you add 2 Everytime

=24+2+2+2+2+2+2+2+2+2+2+2+2+2+2+2+2+2+2+2+2+2+2+2+2

=24+48 seats

=72 seats are there in total