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
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
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
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