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24 votes
24 votes
The 15th term of an arithmetic series is

143 and the 31st term is 183.
a) Find the first term and the common
difference.
b) Find the 100th term of the series.

User Dustin Spengler
by
2.6k points

1 Answer

22 votes
22 votes

Answer:

-1557

Explanation:

a+14d=143

a+12d=183

--------------------

2d= -40

d= -20

a=183+240=423

a(100th)= 423+99*-20=423-1980= -1557

I hope that help =)

User Gagan Raghunath
by
3.3k points