Math, asked by sivakeerthy0606, 11 months ago

in a theater there are 20 seats in the first row and 30 rows were allotted . each successive row contains two additional seats than its front row. how many seats are there in the last row​

Answers

Answered by haridasan85
5

Answer:

This is inArihmetic progression

20, 22,24,26......

a=20

d = I

n=30

Sum=n/2{2a+(n-1)d}

= 30/2{2x20+ (30-1)x1 }

= 15{40+29}

= 15x69=1035 seats TOTAL

seats in the LAST ROW

a+(n-I)d=20+ (30-1) x1

20+29=49 seats

Answered by amrinfathima2005
14

Answer:

Step-by-step explanation:

In the given question is in AP

The seats are increasing by 2 for every row

20,22,24.....

Therefore

a=20

d=2

n=30

No of seats in last row=a+(n-1)d

=20+(30-1)×2

=78

Similar questions